Predictions of the economic losses for the Government following a ban on new oil and gas exploration are being seen as flimsy.

Officials from the Ministry of Business, Innovation and Employment are estimating the ban will cost almost $8 Billion between 2027 and 2050.

Acting Prime Minister Winston Peters says as an academic exercise it wouldn't pass first muster.

Peters told Mike Hosking the gap they have in their calculations is from $200 million to $22 billion.

"When you have that sort of variance you have to ask why don't they go back to the drawing board to get some more respectable figures."

LISTEN ABOVE AS WINSTON PETERS SPEAKS TO MIKE HOSKING