Reaction has been generally positive to today's government announcement that the Transmission Gully route on the outskirts of Wellington is to go ahead.

But the decision has drawn opposing views from the region's mayors.

Transport Minister Steven Joyce this morning confirmed the project would go ahead as one of the Government's roads of national significance.

The upgraded route from Wellington Airport to Levin was expected to save drivers between 23 and 33 minutes during peak times and between 17 and 23 minutes at other times.

Wellington Mayor Kerry Prendergast said the decision paved the way for action to tackle the region's worst bottlenecks.

"We recognise that more work is needed to put flesh on the bones of individual schemes, but for the first time, the Wellington Northern Corridor plan puts Transmission Gully within the context of the region's wider needs.

"As long as the funding is available, construction of Transmission Gully will not now jeopardise other major projects."

Porirua Mayor Jenny Brash was "delighted" with the Government's decision to help fund the project.

"Transmission Gully provides better community and environmental outcomes while also delivering a safe four-lane route for the region.

"The Wellington Northern Corridor from Levin to Wellington Airport is long overdue and needs to be the priority roading project for the Wellington region - indeed for the whole country."

But Kapiti Mayor Jenny Rowan was "extremely disappointed" by the decision.

"This will damage the district forever," she said.

"This expressway will not provide good local transport solutions for people in Kapiti. People in Waikanae will still have to use the old SH1 to drive to Paraparaumu.

"Despite the map being sent to affected parties today, we have been advised there will only be three access points onto this expressway."

Ms Rowan said the route would bring little long term economic benefit to the district - "and this is at a time when the Government is looking to kick-start the country out of a major recession".

Ohariu MP Peter Dunne, was thrilled with the decision, calling it a "great Christmas present" for Wellington.

"After more than 15 years campaigning for Transmission Gully, I'm over the moon at the Government's decision, which should end the more than 70 years of uncertainty about Wellington's northern access and egress once and for all," he said.

"It's been a long battle, but a battle worth fighting."

Greater Wellington chairwoman Fran Wilde said the decision would be "warmly welcomed by most Wellingtonians".

"Some will not like parts of it, but generally it's the first time that we've had a comprehensive funded package so for us it's a great day."

Tolls had been discussed as a way to help pay for the road, she said.

"It's a great Christmas present for the whole region and in fact for anybody who wants to move and send goods between the North and the South Island - the first time that Wellington has been acknowledged as having probably the most difficult part of State Highway One in the whole country."

Automobile Association's Wellington district council chairman John Christianson said today was a great day for the region.

"Today's announcements show great vision for Wellington. It went well beyond what we were expecting because it's dealt with the whole route from Wellington Airport to Levin. It's a Christmas package that will keep a lot of people smiling for a long time."

Transmission Gully Action Group chair Grace Osvald said the capital city would have roading resilience for the first time in its history and not have to rely on the fragile coastal route in the event of a civil defence emergency.

The New Zealand Contractors' Federation applauded the Government's "vision and commitment to the Wellington Northern Corridor".

"The economic and social benefits of this 10-year project will be enormous and it will help to stimulate growth and prosperity throughout the lower North Island," NZCF chief executive Jeremy Sole said.