The Prime Minister has dismissed a Green Party policy to create an independent policy costing unit in Treasury, saying it wasn't a priority.
The Greens had sent letters to leaders asking for cross-party support on the idea, and they're not surprised John Key isn't a fan.
In her State of the Union speech yesterday, co-leader Metiria Turei detailed the Policy Costing Unit plan, which she said would "cut the spin" and bring clarity to the political system.
She estimated the cost of the unit would be between $1 million and $2 million a year, but would increase in election years.
At his post-Cabinet news conference yesterday, Mr Key said the policy wouldn't achieve what it would set out to do and parties could just ignore the numbers.
"I can see why the Greens are worried about the costing of their own projects and Labour's because they're obviously usually pretty large. I don't think it it's a terribly good idea."
Political leaders have their own budgets they can use for costing their policies, though Mr Key accepted the Greens has less money than Labour. It has even less than the Government.
The Green Party says it is "disappointed, but unsurprised" Mr Key hasn't supported the policy.
"This National Government doesn't get its numbers independently checked like we do, and as a result they promise to spend more than they have -- a prime example being the assets sales spending.
"By refusing to support the idea, which is very common overseas, the National Government is denying New Zealanders a chance to make informed decisions on unbiased opinions," Ms Turei says.