History
We have a long history as New Zealand's leading Environmental and Engineering Consultancy. In many ways it’s New Zealand’s history as well, as you will see. Here’s a brief summary of our journey, started more than 50 years ago. As we all know, being aware of where we came from, helps us appreciate and understand where we are going.
In the Beginning...
Ralph Tonkin and Don Taylor met in 1956 when they both worked on the construction of the Auckland Harbour Bridge. In 1959 they formally established Tonkin + Taylor, Consulting Engineers.
The partnership soon grew and was responsible for some notable projects including the lower Waikato Rivers stop banks, investigations for the Marsden Point Oil Refinery, and the innovative Whau Valley Dam for Whangārei's water supply.
T+T ventured overseas for the first time in 1969 when Ralph joined a New Zealand Government Colombo Plan mission to Malaysia and Indonesia.


During the 1970s
Tonkin + Taylor opened an office in the capital and became a founding member of the Engineering Export Association of New Zealand (ENEX), Asia New Zealand Development Consultants (ANZDEC) and Geothermal Energy of New Zealand (GENZL). These organisations brought consortiums of New Zealand consultants together to bid on large overseas projects.
Some of the major projects T+T worked on during the seventies included: The Aniwhenua Hydroelectric Scheme; foundation investigations and ground improvement for the Huntly Power Station and the Mangatangi Water Supply Dam. Overseas, the Kelantan River Basin Study and the East-West and Gua Musang-Kuala Krai Highways in Malaysia were huge projects.
A different structure, even for engineers
In 1981 the practice was restructured from a partnership to a limited liability company but it was done differently from most other companies. With the agreement of the founding partners, the new ownership model essentially became an employee-owned company – a model that continues successfully to this day.
This was the time of Rob Muldoon’s ‘Think Big’ projects of course and once again we were to the fore. As a result, the sheer scale of projects undertaken increased significantly. As an example, we were responsible for the pavements, foundations and water supply for BHP New Zealand Steel at Glenbrook. Other notable projects included the Te Marua Lakes for Wellington water supply; the Maitai Dam for Nelson water supply; LPG storage sites throughout New Zealand and the East Malaysia mini-hydroelectric projects.
In 1985, Ralph Tonkin passed away and three years’ later Don Taylor retired. Terry Kayes was appointed Managing Director in January 1989.
Another change...for good
In the 1990s we changed our title to Environmental and Engineering Consultants to reflect the increasing emphasis on environmental issues and the changes to the range of services we provided.
It was the way of the future and we were among the first to recognise that and adapt.
Overtures from bigger companies were made to us about merging, but in keeping with our founding principles we decided instead to be an independent, specialist, New Zealand consultancy working in the Asia Pacific region. Terry Kayes spoke about this in an interview with the NZ Herald HERE.
The company’s first External Chairperson, Don Christiansen, was appointed. He was succeeded by Dr John Hood, Vice-Chancellor, University of Auckland, after Don took up a lead international role with KPMG.
Once again the historical blending of business and academic excellence were preserved and strengthened.
Some notable project achievements included landfills at Redvale and Silverstream, the Vector tunnel for high voltage electricity transmission to Auckland’s CBD, State Highway 20, ground improvement for the foundations for Te Papa (Museum of New Zealand), and the Opuha Dam for irrigation and hydro-electric generation.
The new millennium
Since 2000 we have continued to grow. As a large environmental and engineering consultancy these days, we have a depth of knowledge and expertise which we leverage by being nimble and responsive problem solvers.
So while Tonkin + Taylor’s journey went from four staff to 600, our expansion was carefully planned and monitored.
Changes in leadership saw Peter Millar appointed as Group Managing Director in 2006, following the retirement of Terry Kayes. Bill Thurston, previously Managing Partner of Bell Gully, succeeded John Hood as External Chairperson when John took up the prestigious appointment of Vice-Chancellor at Oxford University.
Key acquisitions were also made in the 2000s, including the purchase of EDCOP in the Philippines and the purchase and rebranding of The Chadwick Group as Chadwick T+T.
Since 2010...
Peter retired as Managing Director in 2010 after leading us through our 50th year celebrations. Because of our continuing growth, his role was divided in two. Doug Johnson was appointed to Managing Director (NZ) and Tony Kortegast was appointed Managing Director (International). Bill Thurston stood down as External Chairperson and was succeeded by Dr Lester Levy, Chief Executive of the New Zealand Leadership Institute at the University of Auckland and Professor (Adjunct) of Leadership at the University of Auckland Business School.
Jenn Bestwick succeeded Dr Lester Levy as T+T Group Board Chair in 2020.
2021 saw Tim Fisher and Penny Kneebone succeeding Managing Director Doug Johnson with two new roles - Tim Fisher as Group Managing Director and Penny Kneebone as T+T NZ Chief Executive.
Our Australian operation was restructured in May 2010 to provide professional consulting services, including Tonkin + Taylor Pty Ltd, and site investigations, drilling, pavement and geotechnical testing meant the creation of Chadwick Geotechnics.
The projects we are involved in today span the full range of civil, environmental, geotechnical and water resources engineering. We know we are only as good as our last project, and we continue to strive to maintain our reputation for excellence and quality.