Ardern said National had included the cost of the Royal Commission of Inquiry into Abuse in State Care and the Pike River recovery.
She said if National did not believe they were appropriate, that was their prerogative.
"But they are two significant parts of the costs that they have used and I would argue are things that, broadly, New Zealanders support."
According to figures released by the National Party, the Government is spending $700,000 a day on inquiries.
The Opposition also claimed 206 reviews and working groups had been called for by the Government at a total cost so far of about $280 million.
National Party leader Simon Bridges told the Herald on Sunday the coalition Government had outsourced the job it should have done when in Opposition and had virtually added another tier to Government in jobs for Wellington consultants and retired politicians.
State Services Minister Chris Hipkins said yesterday that National had its numbers wrong and described it as "a lazy piece of research".
"National have listed a lot of items as reviews or working groups that aren't and are actually core government work," Hipkins said.