The Government and Auckland Council are being asked to cough up an extra $500 million each for the city rail link project.
Costs for the project have blown out massively, now costing nearly $4.42 billion.
Both local and central Government says they're committed to the project.
Auckland Mayor Phil Goff told Larry Williams that walking away from this project is not possible, but they are not happy with what's happened.
"We can't do without it. Was the cost escalation expected? Yeah. Was it welcome? No."
He is promising that rates will not be raised in order to fund it.
Goff says that previous government and council did not account for a number of things, which is one of the reasons for the blowout.
"One of the things they got wrong was they didn't future proof it. A quarter of the amount of money we're putting in overall is to increase the size of the stations so we can fit bigger train."
If they didn't build it now, then they would have had to close the stations later on in order to make them bigger. Goff says that increasing the station sizes alone will cost around $250 million.
Despite the blowout, Goff is confident it won't hit $6 billion, as both council and the Government hired separate firms to evaluate the cost, and they are now more confident about the future costs.
"You've got two critical groups going in there, giving us some confidence that this figure is more likely to be realistic.