The Government's preferred option to remake Wellington's transport infrastructure includes light rail from the city centre to the south coast.
The option has trains connecting Wellington's central train station to Island Bay, an extra tunnel through Mount Victoria for buses, bicycles and walkers, and rearranging roads around the Basin Reserve.
If the light rail option was too expensive it would explore using buses instead.
The plan is part of the $6.4 billion Let's Get Wellington Moving programme, a partnership between the Government, Wellington city and regional councils, and Waka Kotahi.
However, the councils and Waka Kotahi are yet to agree to take the proposal to the business case phase.
There are no indicative costs released with the plan, nor many details.
Infrastructure Minister Grant Robertson said it was a once-in-a generation opportunity to reshape the city.
"[To] align transport and urban development, and help to address the climate crisis by moving more people with fewer vehicles."
Light rail would help service the significant amount of new housing needing to be built in the coming decades to accommodate up to 80,000 new residents expected to be living within the city limits, Robertson said.
He expected a 25 percent increase in the number of people coming into the central city each workday from across the region.
"Light rail will support more people living centrally, close to where they work, study and live their lives," Robertson said.
Transport Minister Michael Wood said: "Our capital needs a linked-up rapid transit transport network that will serve Wellingtonians into the future, making it faster to move through the city, connecting communities, providing greater access to businesses, all while reducing congestion,"
Illustrations released by the Government appeared to show a change to two-way traffic in some parts of the Basin Reserve, and an extension to the Arras Tunnel under the Pukeahu National War Memorial Park. They also showed the current Mount Victoria tunnel converted to walking and cycling only.
Information on LGWM's website indicated the light rail or bus options would have dedicated lanes in parts of the network. It expects the morning commute from Island Bay to the train station to shorten by 12 minutes - from 35 minutes to 23 minutes.
It appeared the plan was for either option to run down Kent/Cambridge Terraces. It also indicated local traffic would be physically separated from northbound State Highway 1 traffic at the Basin Reserve area.
Green Party infrastructure and transport spokesperson Julie Anne Genter said the option the Government favoured would cost the most and have the largest climate emissions.
She said it was not clear how this plan fitted with the Government's climate goal to cut the number of kilometres travelled by private fossil fuel cars by 2035.
The LGWM programme was officially launched in 2019 but has been beset by problems and delays - with so far little in the way of concrete action apart from speed limit reductions in the inner city.
Stuff reports Treasury analysis that the $6.4 billion pricetag is likely to increase significantly.
Funding for the programme is split with the Wellington councils funding 40 percent and the Government picking up the rest of the tab.
RNZ
