A public transport advocate says the government may need to step in if the deadline for Auckland's long-anticipated underground rail network is pushed out.
City Rail Link chief executive Sean Sweeney said he could not guarantee it would hit its opening deadline of 2026.
The project has suffered several budget blowouts and will cost the city $220 million a year once it opens.
Auckland Council's Budget Committee is meeting this week to look at increasing rates to meet "unavoidable" cost pressures brought on by the City Rail Link.
The city's mayor is proposing an 8 percent rates increase for the financial year 2026 to 2027, as part of the council's 10-year budget, to soften the blow of City Rail Link costs.
The promise of an underground network stretching out from Auckland's city centre has been on the cards for seven years now.
Public Transport Users Association national coordinator Jon Reeves said Aucklanders were keen to see the rail network open.
"I think all of Auckland is just eager for it to open, it would be great if City Rail Link Limited can somehow pull finger and somehow deliver what the city needs," he said.
Reeves said it could be time for the government to step in.
"Maybe the government needs to step in here and really put some close scrutiny on City Rail Link Limited, and see why it's constantly missing deadlines," he said.
"Everyday it's not operational it's costing the city and the taxpayers a lot of money, and we need to get this open ASAP to alleviate congestion across Auckland."
Reeves said he had his fingers crossed the underground rail network would open on time.
"We can't really drag it out any longer."
However, Sweeney told Nine to Noon the target opening date of 2026 could be just out of reach.
"We have a contract completion date of late November, 2025," he said.
"That is what we call a P50 date, we always work to P50s, and that means it has a 50 percent probability of being met and a 50 percent probability of not being met, that's the date we're working to."
There was still a huge amount of testing which needed to take place before the underground could be opened to the public, Sweeney said.
"We're responsible, basically, for handing over a railway that is able to be operated by Auckland Transport," he said.
"Once we've handed it over, they have to do a fair amount of work learning how to operate it so that it's ready for public operations."
Not just that, they would need to add years to guarantee an opening date with certainty.
"If people wanted a guarantee, you'd have to put years onto that date, if people wanted a locked in guarantee that was certain to be achieved, and that would be unwise," Sweeney said.
The Ratepayers' Alliance also hit out on the delays, calling the project a symbol of financial incompetence.
The Ratepayers' Alliance said even if the proposed rates increase for the underground's expected opening were to go through, it would take the annual rates of about 72,108 ratepayers just to cover the network's $220 million a year running costs to the city.
Auckland Mayor Wayne Brown is looking to put up rates by 8 percent in year three of the 10-year budget, to cushion the blow of City Rail Link costs coming in.
Auckland councillor and Transport Committee chair John Watson said any delays from the project would try passengers' patience.
"Any more unexpected delays from here on in would, I think, be stretching the patience of the public, but also would have ramifications for that up-surge in patronage across the network as a whole," he said.
The council will discuss the City Rail Link at its Budget Committee meeting on Wednesday.