talks with lenders positive

Debt-laden OZ Minerals Ltd is still in "very positive" talks with its lenders, the miner says, after its shares dived on concerns that its bankers may go ahead and demand repayment of a loan this week, despite an agreed takeover bid.

"We're in very good, productive talks with the banks, with a view to getting the extension we need by Friday," Oz Minerals' executive general manager, Bruce Loveday, told Reuters.

"The discussions are very positive," he said.

The world's second-largest zinc miner, due to repay at least $140 million in loans by Friday, agreed this month to a $1.7 billion takeover from Chinese state-owned metals trader Minmetals, but the deal still needs Australian approvals.

Oz Minerals shares were down 14.52 per cent at 50 cents at 1156 AEDT, well below Minmetals' 82.5 cents offer.

Treasurer Wayne Swan, who has a veto over foreign investment in local firms, said no determination had been made yet on the Minmetals-Oz Minerals deal.

Earlier on Wednesday, Bass Metals Ltd said its exploration partnerships with OZ Minerals had been terminated and OZ Minerals would lose any rights to the joint ventures.

"The termination of the alliance and joint ventures, which covered prospective targets in the Hellyer region, was by mutual agreement but initiated by OZL due to exploration budget constraints," Bass Metals said in a statement.