President Robert Mugabe has rejected the appointment of an African Union envoy to help solve Zimbabwe's political problems, the envoy has said.
President Mugabe's government faces expulsion from the IMF
Former Mozambique President Joaquim Chissano said Mr Mugabe felt there was no need for talks with the main opposition party, the MDC.
South Africa has been pushing for talks as it considers giving an emergency loan to help Zimbabwe pay its debts.
Zimbabwe is going through an economic crisis, with shortages of basic goods.
The MDC accuses Mr Mugabe's government of harassing its supporters and rigging elections.
Mr Chissano was appointed earlier this month by African Union Chairman, Nigerian President Olusegun Obasanjo.
"It is an internal problem that they can handle through the democratic institutions in Zimbabwe," Mr Chissano said he had been told by Zimbabwean officials.
The former Mozambique leader, who stepped down earlier this year, however said he felt that Zimbabwe could benefit from outside mediation.
Joaquim Chissano is one of the few African leaders to step down
"My opinion is yes, the world must help Zimbabwe to solve their problems - when they request that."
He was speaking at a summit of Southern African leaders.
The summit, to mark the 25th anniversary of the foundation of the Southern African Development Community, Sadc, is going to discuss democracy and political stability in the region but will not directly tackle the problems in Zimbabwe.
Earlier this week, South Africa's deputy Foreign Minister Aziz Pahad denied that South Africa wanted to see a coalition government in Zimbabwe but said it wanted to see economic reforms.
"We are negotiating in the... broad context that we need fundamental economic changes, and how do we minimise the political tensions of Zimbabwe without necessarily talking about governments of national unity," Mr Pahad said.
Zimbabwe needs $300m to repay its debts or it faces expulsion from the IMF.
South Africa's President Thabo Mbeki has indicated that he would be inclined to help but officials are still negotiating over the details.
There are shortages of food, fuel and foreign currency, with rampant inflation and unemployment.