Heavy rain is threatening to disrupt relief efforts in China where 5 million remain homeless nine days after a quake killed over 40,000.

Officials say 3 million tents are needed by survivors of the the 7.9-magnitude quake which hit the mountainous Sichuan province. Officials say the death toll is likely to reach more than 50,000.

Meanwhile, there are fears that reservoirs could burst in quake-stricken areas because of the rain as thousands of aftershocks compound the difficulties of trying to deliver aid to victims.

Chinese Premier Wen Jiabao has ordered experts to inspect dams and reservoirs on 24-hour patrols with more heavy rain forecast.

He said floodgates must be opened to run at low or even empty water levels and the dozens of "barrier lakes" formed by numerous landslides blocking river flows must be monitored.

In Qingchuan county, where more than 2,670 people died, around 9,000 residents were evacuated after huge cracks appeared on the top of a tree-covered mountain. A soldier said: "If it slides, it will take out half the town. The big worry is rain and aftershocks."

Mr Wen has also ordered the supply of 250,000 temporary housing units - simple steel structures normally used by construction workers - to the quake area by June 30 and the number should reach 1 million in three months, state media said.

In Shifang, a small city near Chengdu, almost the entire population has been sleeping outdoors despite the weather.

Wang Falan, who is living with her extended family of 11 in two makeshift shelters, said: "The biggest hardship we have is not having a tent. It is also the lack of rice and cooking oil. I don't know what we'll do if we have to keep living like this."

And the threat of disease means rescue workers are continuing to douse wrecked towns and villages with disinfectant and lime. Over, 5,000 epidemic prevention workers have been sent to 125 villages in the region, the official Xinhua news agency reported.

In Beichuan, the devastation has been so complete that the government is considering abandoning the county seat and rebuilding it elsewhere, making the ravaged town a memorial, local media said. More than 8,600 people were killed in the county.

China began three days of national mourning on Monday, with flags raised at half-mast and public entertainment suspended.

On Wednesday, thousands gathered in Tiananmen Square for a third day, waving flags and chanting "Go China" and "Go Sichuan".

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