The nurses union says after months of negotiations, the State Government has made its members a pay offer.

The Australian Nursing Federation wants a 20 per cent increase over 3 years, and is threatening industrial action if its demands are not met.

It wants to see a nurse's average annual salary boosted over that time from $73,000 to $87,000.

The ANF's state secretary, Mark Olson, says in a meeting yesterday, the Health Minister set out an initial offer of 12.75 per cent over three years, subject to conditions.

"I don't think the nurses are going to be happy or satisfied with that offer," he said.

"I'll always take any offer the government makes back to them, but I don't think the nurses are going to be very happy with that particular outcome."

A spokeswoman for the Health Minister, Kim Hames, says no formal offer has yet been made and negotiations are ongoing.