The creation of a 3000km national cycleway moved a step closer yesterday when Prime Minister John Key took charge of the plan, indicating it would cater for all cyclists.

Mr Key called the idea, presented in the Jobs Summit last month, a "serious initiative".

He said the cycleway could be paved with concrete so it was suitable for a range of bikes.

Other options put forward by officials had been for it to be unpaved or tar-sealed.

But, "in the modern world people use a mixture of mountain bikes and semi-road bikes - which probably argues for paved".

Mr Key said he met officials yesterday. They were working "actively and aggressively" on a plan.

He had no idea what route the cycleway would take, except that it would go from "Kaitaia to Bluff".

The officials were also looking at whether the cycleway could be linked with parts of Te Araroa walkway, a 3000km tramping route the length of New Zealand.

Mr Key said the cycleway was "a long-term thing that New Zealanders will look back on and be proud that they've got".

"It is a serious initiative and while there is a quirkiness about it, in our opinion it could be a major tourist activity - both domestically and for international tourists."

He said it could create "a lot of potential jobs" although it was too early to say how many or when it could start.

The $50 million cost estimate made at the jobs summit was a "rough, back of a piece of paper determination".

Te Araroa founder Geoff Chapple said it would be difficult for bikes to travel along much of its route.

It included steep and rugged terrain and would often be "really difficult mountain bike tracks".

But parts of the route, such as that along the canal between Tekapo and Twizel, that took bikes.

Other parts of the route that could instantly become part of the cycleway included the central Otago rail trail.

Mr Chapple said the cycleway was a great idea, but would be very hard to achieve.

He said a cycleway needed a level gradient, which was not found on State Highway One, and that cyclists would rather not travel too closely to cars. The main trunk railway would provide a level route, but viaducts might have to be built to carry cyclists across streams.

Te Araroa, which had a start cost of $5 million and needed another $6 million to finish, stitched together existing tracks and then gained access to fill in the gaps, he said.

"It pays to be an optimist," he said.

* Comparing lengths

3000km: Estimated length of the national cycleway throughout New Zealand

6400km: The Great Wall of China