National says Labour's pledge to build a light rail link to Mt Roskill early is pork-barrel politics because there is a by-election on.
Labour leader Andrew Little announced on Sunday he will prioritise a $1.3 billion light rail project from the CBD to Mt Roskill if he becomes Prime Minister in 2017.
The 13km line would take passengers from Wynyard Quarter to Britomart and Dominion Rd via Queen St and terminate in Mt Roskill.
There is a by-election in the Labour-held seat of Mt Roskill because Phil Goff resigned when he became Auckland's mayor.
National's by-election campaign chair Steven Joyce says the pledge looks desperate.
"This is taking pork-barrel politics to a whole new level. If this is the sticker price for a Labour Party by-election campaign, all the other electorates across New Zealand will be asking for their $1.4 billion," he says.
Mr Little says he's bringing forward a plan that's already there.
"It's not a bribe," he said.
He didn't give a time frame. The project is currently expected between 2028 and 2038.
Mr Joyce questioned if Mr Goff had "a lazy $700 million lying around" for the city to pay half the cost.
"Mr Goff is out there saying the council is short of money."
Mr Little said his Government would foot the bill for $680 million of the total cost.
Money could be re-prioritised from the Land Transport Fund to pay for the Government's share of the cost, without the need for other taxpayer fundraising.
Auckland Council would be expected to pay the other half, though the 50/50 split had not been agreed to and was still "subject to negotiation", Mr Little said.
The Mt Roskill by-election is on December 3.