UNITED NATIONS - UN chief Ban Ki Moon on Thursday called on Zimbabwe to immediately lift restrictions on the delivery of humanitarian aid to hundreds of thousands of civilians in order to avert catastrophe.

Only 280,000 of the 1.5 million Zimbabweans in need have been able to receive aid so far, the UN secretary general said in a statement.

'I am deeply concerned about the humanitarian situation in Zimbabwe where, despite requests made by the United Nations Country Team and other humanitarian partners, operations of voluntary and non-governmental organisations remain restricted', he added.

The Harare government's decision in June 2008 to restrict field operations must be 'lifted immediately so that aid organizations can carry out their relief work and avert a catastrophic humanitarian crisis', the UN boss said.

Zimbabwe's President Robert Mugabe, who was re-elected in a June 27 one-man runoff widely regarded as a sham, is trying to work out a power-sharing deal with opposition leader Morgan Tsvangirai and Arthur Mutambara, head of the smaller faction of the opposition Movement for Democratic Change.

Mr Tsvangirai boycotted the run-off despite finishing ahead of Mr Mugabe in the March first round of the election, citing rising violence against his supporters that had left dozens dead and thousands injured.

Zimbabwe moved to suspend exports of basic commodities late last month amid the political crisis and chronic food shortages.

Basic foods such as sugar, bread, cornmeal - the national staple - and cooking oil are often in short supply in Zimbabwe, which was once a regional breadbasket.

The country's economy has been in meltdown, with the world's highest inflation rate officially put at 2.2 million per cent and major food shortages.

At least 80 per cent of the population lives below the poverty threshold. -- AFP