The Minister of Transport is playing down the prospect of a government contribution to extending the runway at Wellington airport.
The company that runs Wellington Airport wants to extend the runway 300 metres southwards into Cook Strait.
It said it would enable far more tourists to come from Asia to Wellington by allowing long haul flights to land in the capital. The work would cost $300 million.
Wellington regional mayors said they will fund half the cost, if the Government also put in money.
Minister Simon Bridges said he was waiting for a business case to cross his desk but in the meantime he had his doubts.
"I'm sceptical. I think whilst there would be regional advantage, the case that I would want to see is the case for a national advantage to New Zealand in spending a very significant sum of money on extending that runway.
"I think pure regional advantage wouldn't be sufficient to see the government involved."
Mr Bridges said the listed company Infratil which owns two thirds of Wellington airport would be a private sector beneficiary of any Government input.