FOUR men who camped beside the flood-swollen Nepean River at Penrith in western Sydney had to be rescued yesterday after they were found clinging to trees.

Three of the men, who were in their 20s and 30s, had to be winched to safety by helicopter and were taken to nearby Nepean Hospital suffering from hypothermia.

In another incident following the worst storms around Sydney and the Hunter in more than 30 years, 12 private school children and two teachers spent a cold, wet night in the Blue Mountains after trekking through the Megalong Valley on Saturday.

The group became concerned about their safety and set off an emergency beacon. Unable to reach them by helicopter because of low clouds, four emergency workers attempted a trek to their position but could not get there by nightfall and were also forced to spend the night in the bush.

Blue Mountains Local Area Commander, Superintendent Pat Paroz, said police would speak to the principal and teachers at the school about the incident.

“What we want to find out is, what was considered before the event was undertaken, what planning was put in place, what arrangements were made,” Superintendent Paroz said.

North West Region Commander, Detective Assistant Commissioner Denis Clifford, said he would also express his concerns to the Duke of Edinburgh Awards organisers.

“I will be seeking to meet with the organisers of the Edinburgh Awards to discuss any future events which are planned in these conditions which could potentially put the lives of not only the participants at risk, but the rescuers as well,” he said.

Two students suffered mild hypothermia, and one of the teachers sustained a knee injury during the ordeal.

The NSW State Emergency Service reported they had cleared more than 16,500 requests for help since the storms began 10 days.

There were 80 teams of about 400 volunteers in the field yesterday, supplemented by volunteers from the NSW Rural Fire Service and officers from the NSW Fire Brigade.

Another 100 volunteers arrived in the central coast and Hunter regions last night from the Queensland to assist with the remaining 1300 requests for help.

The Bureau of Meteorology has warned that more substantial falls predicted for mid-week could cause further flooding in the Hunter Valley and central coast.

“We have a day and a half at least of intense weather,” senior meteorologist Neale Fraser said. “It looks like we’ll be in for probably gale-force winds again in coastal areas and the rainfall will be more than we had today, but nothing like last weekend.”

Snow is expected to coat the Victorian and NSW ski fields early in the week, boosting the ski season.

And Sydney’s long-parched catchments are finally beginning to fill.

Sydney Catchment Authority spokeswoman Shannon O’Connel said dam levels were expected to reach 45 per cent later this week, the highest level in three years.

“It’s very welcome, and the fact that the catchment is wet from the previous week means much of the rain is running straight off into the dams,” she said. “It has been significant rain.”