Defence Minister Gerry Brownlee has defended a $100 million blowout in the cost to upgrade the navy's two frigates.
The Defence Force is in the process of upgrading the combat management systems, radars and sensors, and replacing the self-defence missile systems, on both the HMNZS Te Kaha and the HMNZS Te Mana.
It was originally budgeted to cost between $354m and $374m, but Labour MP Phil Goff says it's now expected to cost close to $473m.
Mr Goff also said the upgrade work won't now be completed until March 2019 - 13 months later than planned.
He sought an explanation from Mr Brownlee when he fronted up to Parliament's foreign affairs, defence and trade select committee on Thursday.
"How do you explain any cost blowout? It's what it costs to get what you want," Mr Brownlee said.
Despite the fact Treasury has raised concerns about the project, the Government is committed to pressing ahead with it, he said.
"It won't matter how many times Treasury gets upset about the expenditure on something that they don't agree with, they don't put their name on a ballot paper, they don't stand on street corners talking to constituents, they don't have a responsibility for the security of New Zealand," Mr Brownlee said.
"It's a capability the Government wants, it's the capability the Government's paying for, it's a capability we're going to get."