DALLAS (AP) _ Attorneys for the Hunt brothers say they oppose a proposal by the Internal Revenue Service that would settle the agency's $350 million tax claim against Placid Oil Co. for $60 million.

Placid, which filed for protection from creditors under Chapter 11 of the federal bankruptcy law, and its creditor banks have filed competing plans for debt reorganization.

Placid, owned by Lamar, Nelson Bunker and William Herbert Hunt of Dallas, owes 18 bank creditors about $810 million. The debt is secured by virtually all of the independent oil company's oil and gas reserves.

The IRS is Placid's second-largest debt holder, behind the creditor banks.

The government's offer is for $60 million cash and an adjustment in tax bases that would result in Placid paying an additional $30 million, Placid attorney J.K. Skillern said Friday.

''Placid is opposing the settlement very strongly,'' he said.

The Hunt plan allotted $45 million for the IRS claim and creditor banks increased the offer to $50 million in their plan. Two weeks ago, U.S. Bankruptcy Judge Harold Abramson allowed the banks to negotiate with the IRS.

Abramson scheduled hearings March 7 and 8 to consider the IRS claim.