South Sudan has sold 33.4 million barrels of oil to international buyers at an estimated value of $3.2 billion, despite a deadlock in negotiations with the north on the industry, the oil ministry said on Monday.

"As from July 9, 2011 to December 31, 2011, South Sudan has sold 33.4 million barrels (of oil) at the amount of $3.2 billion from the producing blocks," Minister of Petroleum and Mining Stephen Dhieu Dau said in a statement, referring to sale agreements for the period until the end of the year.

The newly-independent country, which seceded from the north in July, is one of the poorest in the world and depends on oil for 98 percent of its income.

But Juba and Khartoum are locked in a bitter dispute over the fees that the south owes for using the north's oil export infrastructure, which South Sudan currently depends on to reach the international market.

The oil ministry said state-owned Sudanese firm Sudapet would "no longer receive any entitlement from South Sudan's crude oil or sit on the boards of operating companies when they make decisions on South Sudan's resources."

"The ministry has also informed all foreign oil companies and potential buyers of South Sudan crude oil that no other nation or entity has been authorised to sell its oil," it added.

Any violation of this decision could jeopardise new contracts between South Sudan and companies which operate producing blocks due to be signed by the end of the year, the ministry warned.

Juba issued a presidential decree earlier this month transferring Sudapet's shares in the southern oil concessions to the south's national oil company Nilepet.

The move was condemned as uncooperative by the Sudanese government, which lost three quarters of its total crude output of about 470,000 barrels per day when the south seceded in July.

But the southern oil ministry said Khartoum had finally agreed to what "was a legitimate act of sovereignty".

The ministry was unavailable for comment on the current rate of production but said last month that since Khartoum had pulled out all its skilled labourers and subcontractors from the south, oil output had fallen from pre-independence levels.

In a bid to kick-start the floundering talks, former South African president Thabo Mbeki, who heads the African Union's mediation efforts, met the Sudanese negotiating team in Khartoum on Sunday to discuss pending economic issues.

But no details emerged and it remains unclear when direct talks on oil will resume.