China's new high-speed train "Fuxing"can travel 350 kilometres per hour. However, New Zealand's possible rapid rail will not be at the same level as the bullet trains, Twyford said.

New Zealand's first rapid rail service may be launched between Hamilton and Auckland, allowing commuters to travel between cities in just an hour.

The Government has confirmed they are investigating options for an express service that would see passengers catch a train in Hamilton and reach Auckland's Britomart in 60 minutes.

It comes as the Hamilton-Papakura service, Te Huia, now has a confirmed start date of August 3.

That service allows travel from The Base to Papakura in 80 minutes, but transferring to Auckland's CBD will currently take an estimated two hours, 20 minutes.

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Minister of Transport Phil Twyford said cabinet had approved an initial business case for the rapid rail service, due mid-year. A detailed business case would be required after that.

He called the rapid rail plan a "nation-building" project.

"The idea is you would link two of the most important housing markets and job markets in New Zealand," Twyford told Stuff.

Allowing such a quick transfer between centres would support growth along the Hamilton-Auckland corridor, he said.

"There's going to be huge growth in this corridor - population growth, economic growth and development."

People had already moved to Hamilton from Auckland and were commuting during the week, he said.

CHRISTEL YARDLEY/STUFF The Government is investigating rapid rail between Hamilton and Auckland.

"People in Waikato and the Bay of Plenty need to get to Auckland for business, work, for recreation, and to get acess to the airport, and yet the southern motorway is such a terrible bottleneck, and that's what we are trying to overcome."

One option being looked at was for a rapid train with only two stops - Hamilton and Auckland - and another option was a fast train that stopped at stations north of Hamilton and in Auckland's southern suburbs.

The Ministry of Transport was looking at a technology known as tilt trains, used frequently overseas, travelling at speeds of around 160 kilometres per hour.

It would require building an entirely new, straighter line, and the trains would be electric.

"You would be talking quite a few billion dollars."

But it won't be like the bullet trains in Japan, Twyford said.

"I wouldn't want to give that impression, though it will be sleek, modern and efficient - no question."

WARWCK SMITH/STUFF Transport Minister Phil Twyford said rapid rail would enable growth between Hamilton and Auckland.

But National MP for Hamilton East David Bennett said the idea was simply government "dangling the carrot".

"Any talk of rapid rail is a pipe dream, that's going to be such a huge financial cost.

"I don't think this Government would even do it."

Bennett criticised the Government for getting the Hamilton-Papakura service off the ground, when key roading projects had been cancelled.

"The extension of the Waikato expressway from Cambridge to Piarere was approved by NZTA, it was a regional priority and the highest priority in the region," Bennett said.

CHRISTEL YARDLEY/STUFF National MP David Bennett said the chance of rapid rail was a "pipe dream".

A planned interchange would have solved some of the dangers on the road, he said.

20,000 people used that route each day, Bennett said, whereas the $90 million train can only take 150 in each carriage.

"It's going to service a very small number of people."

He did not think train services would attract people working in Auckland to move to Hamilton.

"I think there's little chance of that, growth is already booming in Hamilton and a lot of it's down to the expressway.

"At the moment it's quicker to get on the road than on rail, it will be two hours to get to Papakura."