The City Rail Link needs to undergo extensive testing before it can open to the public. Photo: RNZ / Luka Forman
Underground rail construction of Auckland's City Rail Link (CRL) is 80 percent complete but there is no guarantee the November 2025 deadline will be met, the project's boss says.
The CRL project is due to be handed over to Auckland Transport in November 2025.
Preliminary work on the 3.4 kilometre track, spanning four underground stations, from downtown's Britomart to Mt Eden, began in 2016.
City Rail Link Limited chief executive Sean Sweeney told Nine to Noon there was still a huge amount of testing that needed to take place before the underground could be opened to the public.
"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."
"If people wanted a guarantee, you'd have to put years onto that date" - City Rail Link Limited chief executive Sean Sweeney
There was a fifty-fifty chance the project would not come in on time, Sweeney said.
Adding a year to their deadline would provide a higher level of confidence, he said.
"If people wanted a guarantee, you'd have to put years onto that date (November 2025), if people wanted a locked in guarantee that was certain to be achieved, and that would be unwise."
Advising of a date years out has proven to be a problem for international projects, he said.
In March the CRL requested an extra $1.074 billion in funding, bringing the total cost to an estimated $5.493b. Until handover there was a risk of further cost blowouts, he said.
"Anyone that said otherwise would either be or disingenuous, but the risks are getting smaller as we go through."