Some of the party's policies have detailed a few of the costs associated with their plans.
"But with our overall approach, we need to see what impact Prefu has – given the fact things are changing so significantly," Goldsmith said.
Robertson, however, said this was not good enough.
"If you're making the promises now, you need to say how much they are going to cost," he told media in Tauranga this morning.
"National making uncosted policy announcements is reflective of a chaotic environment inside their party."
Last election, when Labour was in opposition, it contracted Berl to cost its policies.
The economic consulting firm looked over what Labour was proposing and made sure there was enough money in the Government's coffers to deliver on their promises.
Goldsmith said NZIER have done the same for National.
Those costings would show that "New Zealanders can rely on us to be careful with their money".
"I'm not going to take a lecture from a Minister of Finance who burned through the massive surpluses he inherited within two years," he said.
Scrapping over numbers is not unusual for National and Labour before an election.
Last election, then-Finance Minister Steven Joyce claimed that Labour had an $11.7 billion "fiscal hole" in its costings.
Robertson disputed this and said Joyce had misread the numbers.
Although many economists dispute the "fiscal hole" argument, there was fairly wide agreement that based on Labour's numbers, there was very little wiggle room for Labour to introduce new spending.
However, with the $50 billion in additional spending – funded by borrowing – that the Government announced to help New Zealand respond to the economic fallout of Covid-19, that argument is more or less now moot.
