The growing range of amphibian craft designed by New Zealand entrepreneur Alan Gibbs has caught the eye of the United States military.

Gibbs Technologies has won a US Department of Defence contract to evaluate its high-speed amphibian technology for military purposes.

The US Navy will test the capability and operational limits of the Gibbs fleet.

The vehicles are the Aquada, an amphibious car, the Humdinga, a five-seater, four-wheel-drive utility vehicle capable of travelling up to 128km/h on land and 72km/h on water, and the recently launched Quadski, a high-speed amphibious quad bike.

The US military interest comes after Mr Gibbs, one of New Zealand's richest men, spent an estimated $50 million on his amphibious technology.

The New Zealand- and UK-based company built prototypes of the vehicles in Britain but spokesman Russell Briggs told the Herald yesterday the contract would involve only the licensing of the technology.

Although the technology was developed for the consumer market, Gibbs Technologies was confident it could adapt it for military use.

It could provide the Navy's special units with a unique high-speed amphibious personnel carrier and offer solutions to traditional problems posed by land-sea borders, such as beachhead landings or crossing waterways and lakes.

Mr Gibbs said the contract was a milestone for the company because "we have solved a problem which has beset every general since Alexander the Great".

He believed the high-speed amphibian technology could have a profound impact on the global military community, and also offered enormous non-military potential for peacekeeping forces and disaster relief agencies.

Mr Gibbs had previously expressed hope in the potential use of his vehicles by farmers and outdoor workers as well as emergency services.

Mr Briggs said the US defence contract gave the company's work credibility. Gibbs Technologies experts would work closely with the validation team and would lead any subsequent application development process.

The Gibbs Aquada, which sells for around $440,000, can reach 160km/h on land and 50km/h on water.

British entrepreneur Sir Richard Branson drove one across the English Channel in 90 minutes.