The New South Wales Treasurer says the state has lost up to $90 million from the issuing of mining exploration licences examined by the Independent Commission Against Corruption.

Mike Baird made the revelation during a budget estimates hearing this morning.

The ICAC has found senior figures in the former Labor government acted corruptly over deals done for the Mount Penny mine.

Last month the ICAC recommended former ministers Eddie Obeid and Ian Macdonald face criminal charges over the deal.

The inquiry heard Mr Macdonald granted the lucrative Mount Penny coal mining lease over land owned by the Obeid family, and that the Obeids encouraged their friends to buy up land in the area.

Several others linked to the deal have also been referred to the Director of Public Prosecutions.

Mr Obeid has rejected the findings, saying they are superficial and biased.

The ICAC is also due to hand down its findings for the Doyles Creek mine soon.

Mr Baird says he asked Treasury and the Division of Resources and Energy to examine the cost to the state of the deals.

He says he was appalled at the result.

Mr Baird says it is impossible to give an exact figure for the amount lost, but the Mount Penny licence would be worth between $30 million and $50 million, while Doyles Creek is valued at between $20 million and $40 million.

"They were the upfront fees that should have been paid in relation to those two licences," Mr Baird told the estimates hearing.

But the hearing degenerated into a shouting match shortly after, as Mr Baird refused to say whether he ever acted on his pledge in September 2011 to have an independent panel make appointments to state-owned corporations.

"You are hiding something, Treasurer, because you are not telling us whether that panel exists or not. Why won't you tell us if the panel exists?" said Greens MP John Kaye.

"There's nothing to hide," Mr Baird said.