Many Zimbabweans now use firewood instead of electricity

Rampant inflation will mean shops and services can no longer function and people would resort to barter, it said.

"The memorandum is talking about a situation where there is no functioning government or a total breakdown," an unnamed aid worker told the UK Times.

Zimbabwe's inflation is already 3,714% - the highest rate in the world.

Business quotes were now valid for just one day or even one hour, said the report written by consultants and sent to workers at the United Nations and other aid agencies.

Several organisations contacted by the BBC News website denied commissioning the report.

Some firms were already partly paying their workers in food, rather than money, it said.

ZIMBABWE CRISIS Inflation: 3,714% Unemployment: 80% 4m need food aid Life expectancy: 37 (men), 34 (women)

Mobiles to beat fuel queues

Shops were doubling their prices twice a month, so they could purchase replacement goods.

If this continues, "doubling the current inflation for each of the seven remaining months of 2007 gives 512,000% thus the economic collapse is expected before the end of 2007," said the report, according to the AP news agency.

The security forces who have remained loyal to President Robert Mugabe were also feeling the effects.

The report said an ordinary police officer earned less than aid workers paid their domestic staff.

It said power and water suppliers were already near collapse. Electricity was last month rationed to just four hours a day to save power for farmers.

Just one adult in five is believed to have a regular job.

Some 4m Zimbabweans - a third of the population - will need food aid this year, according to the UN World Food Programme.

Mr Mugabe denies responsibility for Zimbabwe's economic problems, blaming a western plot to bring down his government because of his policy of seizing white-owned land.