ANXIAN, China - China grappled with backed-up rivers and reservoirs believed in danger of collapse Monday as they, along with looming storms, threatened to compound damage from the country's worst earthquake in three decades.

Two weeks after the magnitude 7.9 earthquake centred in Sichuan province, the confirmed death toll rose to 65,080 with 23,150 people still missing, the government said. The final number of dead is expected to exceed 80,000.

Many of the disaster victims were children - although no specific numbers are known - prompting officials to relax the country's strict one-child policy.

The Chengdu Population and Family Planning Committee in the capital of Sichuan province announced Monday that families whose child was killed, severely injured or disabled in the quake can get a certificate to have another child.

On Monday, 1,800 soldiers arrived on foot at the new Tangjiashan lake in Beichuan county to fight the flood risk, each carrying 10 kilograms of explosives to blast through the debris, the official Xinhua news agency reported.

The lake is three kilometres upstream from the centre of Beichuan county. Thousands of people who remained there after the initial earthquake have been evacuated in recent days as a precaution.

Temporarily clearing weather allowed heavy equipment to be airlifted into the area to help remove debris, the state media reported.

But thunderstorms were forecast for parts of Sichuan later Monday and Tuesday. The China Meteorological Administration said the storms "could increase the risks posed by river blockages in some quake-hit areas."

The rains were likely to put more pressure on dams and reservoirs weakened by the quake. The storms herald the start of the summer rainy season that accounts for more than 70 per cent of the more than 60 centimetres of rain that falls on the area each year.

In An country, about 50 kilometres to the south of Beichuan, a landslide blocked the Chaping River, submerging Shuangdian village.

Residents say the lake has been rising by about 2.3 metres a day.

"The water was covering the road, and two days later I could not see the roof of my house anymore," said Liu Zhongfu, 31, a truck driver who built his two-story wooden house himself, standing on a mountain overlooking the new lake.

A sofa and bits of wood that were once part of houses could be seen floating among the debris in the milky green water.

Liu was working away from home when the earthquake hit. His wife, three-month-old daughter and 60-year-old mother all were unhurt.

"I thought I could go back but I have nothing now. My village, it's all become a sea," he said.

Water there was backed up three kilometres along the river, said Wang Li, county Communist party secretary.

"We need to take care of this soon, this is a serious situation," he said.

Elsewhere, 600 people were voluntarily evacuated from Guanzhuang in Qingchuan county because of landslide worries.

"There's no danger for this exact moment from flooding but we are very worried because the whole mountain is loose," said Ma Jian, a local official.

Problems with dams and reservoirs from the earthquake and its aftershocks also have been reported in other provinces.

The Water Resources Ministry said Monday that three small reservoirs in Shaanxi province, just north of Sichuan, were in danger of collapse after a strong aftershock Sunday. A total 2,383 reservoirs were in danger across the country, the ministry said.

China's top Communist party leaders said relief efforts should now focus more on resettlement and post-quake reconstruction, but that work to find survivors should not stop.

The shift was announced at a meeting of the Political Bureau of the Communist party of China's Central Committee presided over by President Hu Jintao, Xinhua reported.

Meanwhile, the Education Ministry said it would investigate whether flawed construction contributed to collapse of many schools in the quake zone.

"We will punish those who cut corners during school building construction and will have zero tolerance for corruption and shoddy school projects," spokesman Wang Xuming said in Beijing.

In Mianzhu city, the Communist party secretary, Jiang Guohua, pleaded with protesting parents - whose children were killed in a school collapse - not to complain to higher authorities, the Southern Metropolis Daily newspaper reported Monday.

A photograph on the newspaper's website showed Jiang on his knees, his arms outstretched in vain.

"Please trust that the Mianzhu party committee can solve this problem," he begged the parents. "Don't go!"

Despite Jiang pleas, the parents of the 127 children who died kept marching Sunday and eventually met with higher officials, who told them the government would investigate.

The march was the latest example of growing anger among Chinese about the quake, especially the fact that nearly 7,000 schoolrooms were destroyed while school was in session. Parents at several schools have held protests, defying the government's general disapproval of such demonstrations.

Also Monday, Xinhua reported that one of the two pandas still missing after the earthquake had been found.

The panda was recovered earlier in the day, but there were no immediate details given on its condition.

The pandas had been missing from the famed Wolong panda reserve, located near the epicentre in central Sichuan province. The centre suffered heavy damage from the quake and five staff members were killed.