Commuter rail to Auckland's North Shore will go ahead - but the project may still take decades to get underway.
Auckland and the government's transport agencies have confirmed that progress will be made this year to decide whether light or conventional rail will eventually cross the Waitemata Harbour.
However, it could be decades before the project would actually get underway.
An Auckland Transport report, released by the Green Party, shows that even with the current expansion of the North Shore Busway, choke points will appear in a decade's time, and in 20 years up to five stations will struggle.
The busway is one of the city's biggest public transport successes, with patronage rising by 10 percent a year.
Auckland Transport and the Transport Agency said it was always known the busway would reach capacity.
Light rail has previously appeared in reports by government officials, but the politicians who would lead the decision-making - Auckland mayor Phil Goff and Transport Minister Simon Bridges - have been restrained in their enthusiasm.
Auckland Transport is assessing the timing of an eventual switch from bus to rail, to ensure that the tentatively-planned cross-harbour tunnels can accommodate either option.
It was also considering further improvements to extend the life of the busway.