Prime Minister John Key is expected to commit to funding half of Auckland's $2.5 billion City Rail Link (CRL) two years early as part of a wider update on the Government's position on Auckland's infrastructure needs this month.
It's understood Key will commit to the Government's $1.25b co-funding of the CRL project in a speech to the Auckland Chamber of Commerce on January 27.
In 2013, the Government agreed to jointly fund the CRL 50:50 with Auckland Council but to not provide its share until 2020.
It also said the Government would consider an earlier construction start date if it became clear that Auckland's CBD employment and rail patronage hit thresholds faster than current growth rates suggested.
The two thresholds were rail patronage hitting 20 million trips a year before 2020 and a 25 percent increase in Auckland CBD employment over the 2013 level - half the increase predicted in Auckland Transport's City Centre Future Access Study.
Neither threshold has been met at this stage although rail trips are forecast to hit the 20 million mark by the end of this year.
But another factor understood to have tipped the Government's decision to fund the project earlier is the amount of private sector property projects planned or underway along the CRL's inner-city route where it would cost a lot more to incorporate the rail link at a later stage than during construction.
The CRL will link Britomart Station in downtown Auckland with the existing western line at Mt Eden station, allowing trains to run both ways through Britomart.
Simon Bridges, the current duty minister during the Parliament's summer break, said Key's speech was still being worked on, and "comment about its content is simply speculation".
Preliminary work on the CRL started last month and it's unlikely the council would have forged ahead at this stage without a firm commitment from government that its share of the funding would kick in before 2020.