United Nations officials warned yesterday that widespread rain in Pakistan's quake zone could be disastrous for their struggle to contain an outbreak of acute diarrhoea in squalid tent camps.

There have been at least 200 cases and possibly as many as 750 at one camp for homeless quake survivors in Pakistani Kashmir, amid fears that it could be cholera, the World Health Organisation (WHO) and Unicef said.

"Rain would be disastrous," WHO emergency coordinator Rachel Lavy

told AFP at the main camp on the sports ground of the devastated university in the regional capital Muzaffarabad. About 3,000 people are living there.

"Diarrhoeal illness and rain water go hand in hand," she said.

Rain -- the first for six days -started in quake-hit northern Pakistan and parts of Kashmir early Thursday and was due to continue on Friday, while snow is expected at night, the Pakistani meteorological department said.

Winter weather poses the biggest threat to survivors of the October 8

quake, which killed 74,000 in Pakistan and 1,300 in India. UN Secretary General Kofi Annan has warned there could be a massive second wave of deaths.

The disaster left around three million people homeless. The numbers in the camps that have sprung up in almost every town and village are swelling as people come down from the freezing Himalayan mountains.

Aid workers said they were now focusing on preventing lifethreatening diarrhoea at the camps in Muzaffarabad, by teaching people how to keep clean, digging new

latrines and setting up an isolation tent for the sick.

UN officials are still investigating whether the cases are cholera, but added that there are other waterborne microbes that could be equally serious.

"We are taking it as seriously as if it were cholera," said Jan Vandemoortele, the UN Emergency Coordinator in Pakistan. "We are still awaiting confirmation but this is in line with what we have been saying, that sanitation is a potential timebomb."

Disease is on the rise across quakehit areas as cold weather closes in.