A great business is made up of great people.

Darren Diack

Managing Director

Darren has over 40 years’ experience in leadership and management. He spent the first 20 years of his working life at Carter Holt Harvey, and joined Gemco as the Managing Director in 2003. Darren has led Gemco through a period of sustained growth, to become the large successful business it is today. He pins much of the business’s success on three key principles: people, attitude and quality.

Mike Smith

Executive Director and Financial Controller

Mike heads the accounting and administration functions of the business. He delivers timely and accurate financial reporting to the board and management. Bringing the same rigour and attention to detail to Gemco’s financial affairs as the construction professionals bring to their specialist areas. Mike is a highly experienced, qualified Chartered Accountant of NZ (CAANZ).

Chris Olsen

Executive Director and General Manager

Chris takes extreme pride in completing all projects on time and to very exacting standards. His strong belief in honesty and communication being the keys to success are evident in any dealings you have with him. Here from the beginning, Chris knows the ins and outs of Gemco and has formed excellent relationships with clients and subcontractors. With over 30+ years of experience in large complicated commercial builds, multi-story builds and historical renovations, Chris is a handy man to have around.

John Sarten

Non-Executive Director

John is hugely experienced in all aspects of commercial construction and has comprehensive industry know-how. His key role at Gemco is managing the delivery of a high-quality, fully integrated life-care village construction project in Wellington. John is a certified Builder, registered Quantity Surveyor and founding shareholder.

Edwin Brown

Non-Executive Director and Board Chairman

Edwin brings specialist senior management, marketing, strategic planning, and governance skills to the Gemco board. Drawing from his significant commercial and management expertise built up over a lengthy career. He has worked across a variety of sectors including retailing, manufacturing, building, forestry, horticulture, exporting, land development, accommodation and tourism. Today he is a professional Director and company advisor.

Wayne Leadbetter

Non-Executive Director

Wayne joins Gemco's Board of Directors with a wealth of knowledge and business experience built from a career in accounting, private business ownership and other Directorships, both in New Zealand and overseas. Being from the corporate world, Wayne understands the intricacies of business ownership, and is well equipped to provide an outside perspective and direction to Gemco.

Brent McAsey

Operations Manager

Proven strengths in meeting project time frames and client expectations are key strengths for Operations Manager, Brent. He oversees all of our carpenters, supporting them, mentoring them and planning which project they will be working on. Part of the Gemco team since day one, Brent is an integral part of the continued success of Gemco.

Graeme Johnson

Construction Manager

With a wealth of knowledge, and experience across a range of different builds and construction methods, Graeme is an extremely versatile member of the Gemco family. Graeme heads many of our large scale, complex projects, and provides great mentoring to those in his team.

Sam McCarthy

Office Manager

A key player in the Gemco team, Office Manager, Sam runs a tight ship and leads the smooth and efficient running of Gemco HQ. She wears many different hats, managing HR, IT, payroll, marketing, admin and social functions. Sam worked her way up through the business, initially starting with Gemco as the Office Receptionist in 2005. Her hands-on experience and extensive knowledge of the business is invaluable.

Eddie Holmes

Construction Manager

One of Gemco's most experienced Construction Managers, Eddie brings a wealth of knowledge, skill and experience to Gemco and his project team.  Not one to shy away from getting out on the tools, Eddie still has a real passion for getting out there and getting hands on in his projects.

Amy Harris

Health and Safety Manager

Amy is responsible for implementing and improving Health and Safety systems at Gemco. She is passionate about creating an open, honest, and respectful Health and Safety culture within the business operation for employees, contractors, and subcontractors. Looking for continuous improvement and innovation, Amy is always open to suggestions and ideas that help Gemco to lead the way in Health and Safety.

Mathew Shorter

Site Manager

Mathew is our man on the ground at Te Awa Lifecare Village, our high-end Retirement and Health Care Village project based in Cambridge, Waikato. Mathew is a man of many talents, with no task too big or small. With a great approach to all things site related, you can be assured a positive and friendly experience.

Benn Ratana

Construction Manager

As Gemco's main man in Wellington, Ben heads the delivery of a large scale, multi story life care village complex. Ben, as a qualified carpenter, brings a diverse range of skills and practical experience to the Construction Manager role, whilst also providing mentoring and guidance to those in his team. With an eye for detail and high standards, you can be assured a quality build outcome.

Derek Lawson

Quantity Surveyor / Project Manager

Derek has extensive QS and Project Management expertise gained from over 30 years in the industry. With a keen eye for detail, he is very well versed with all budgeting, contract administration, programming, and management needs on construction projects. His technical skills are complemented by excellent people and communication skills. Derek has established invaluable long term Client and Subcontractor relationships over the years for Gemco.

Brad Parkinson

Quantity Surveyor / Project Manager

Brad is an experienced Quantity Surveyor, and with his background in carpentry brings a practical perspective to all jobs. With over 10 years in the industry, Brad has worked on a variety of projects; from high-end residential builds, fit outs, additions and refurbishments, to work in sensitive areas such as early childhood centres, schools, and hospitals.  With his practical experience, estimating and scheduling is a forte of his. Brad's ability to take into account details that may not be included in the initial project procurement, and his understanding of how a building comes together ensures smooth sailing from the very outset.

Brian Smith

Quantity Surveyor / Project Manager

After Brian completed his building apprenticeship, he worked as a builder in the Waikato and Hawkes Bay regions before deciding a move into the role of Quantity Surveyor/ Project Manager was right for him. Learning from the best, Brian has picked up the role fast and is well on his way to developing his skills further, and establishing himself as key player in the Gemco team.

Jade Gardiner

Quantity Surveyor / Project Manager

Ryan Wiggins

Quantity Surveyor / Project Manager

Ryan has worked on a range of projects in the residential and commercial industries ranging from minor dwelling residential units in New Zealand & the South Pacific to multi storey apartment remediation and commercial projects. His history as a professional QS (PQS) providing key skills in understanding his clients needs with regard to setting budgets, client management and liaising with consultants & contractors alike to ensure the smooth delivery of his projects, on time and budget.

Sean Coleman

Electrical Division Manager

Watt would we do without our Gemco Electrical Manager, Sean? Sean runs our team of highly skilled electricians and apprentices with efficiency across all Gemco projects. Whether it be for large commercial projects, small od-jobs, or for our valued clients, you are in excellent hands. Sean has a background of over 25 years in the industry, and joined the Gemco team after owning and operating his own Electrical Company.

Mike Lee

Plumbing Division Manager

A highly skilled plumbing professional, Mike has undertaken a wide variety of roles including pricing and management of contracts. Mike is responsible for managing the Gemco Plumbing team’s work across all projects, from residential to commercial. He is a Certified Plumber and Drainlayer with over 28 years of experience in the industry. Qualified with a NZ Diploma of Business and NZIM Diploma of Business.

Neil McKenzie

Joinery Division Manager

Neil leads Gemco Joinery’s team of tradesmen and apprentices from our Joinery factory in Havelock North. With over 35 years in the industry, Neil is equipped with wide-ranging technical expertise, as well as management and pricing experience.

Jared Gibson

Plasterboard Division Manager

Jared manages our team of experienced plasterers and apprentices over a wide range of both residential and commercial projects. With over 20 years’ experience in the trade, Jared’s passion sees him always striving to get the job done right and on time.

Steph Halstead

Accounts Payable

Steph, our bubbly Scottish Accounts Payable has got you covered. With a great working knowledge of the ins and outs of Gemco, she ensures that all accounts are received and processed on time.

Rylee Diack


As Gemco’s Receptionist, Rylee is the first point of contact both at Gemco HQ, and by phone. With her excellent time management and organisational skills, she keeps on top of the continual comings and goings in our very busy office. Come in and say hello, you will always find Rylee with a warm, welcoming smile.

Steph Schicker

Architectural Designer

Carl Larsen

Architectural Designer

Carl has been with Gemco for over 20 years and has a wealth of knowledge and experience in the Aged Care/Retirement Village developments thru-out NZ, along with other new builds and alterations within the Residential and Light commercial markets nationwide, producing CAD design and consent documentation.