Huge floods in southern China have killed at least 132 people and displaced 800,000, the government said today as the annual storm season picked up ferocity.

Local media showed images of people abandoning their homes in rubber dinghies in Nanchang, Jiangxi province, one of the worst-hit areas.

Many carried bundles of possessions salvaged from the waters that turned the streets into rivers.

More than 10 million people have lost property, been injured or suffered a cut in power or water supplies as a result of the week of torrential rain across Guangdong, Fujian, Guangxi, Jiangxi and Sichuan.

Many of these areas have gone from one extreme to another, according to the government. Earlier this year, south-east China endured its worst drought in living memory, but in the past week, some places have been inundated with three times the average rain for this period.

With thousands of houses destroyed and businesses and power lines put out of action in Guangdong and Fujian – the industrial hubs on the coast – the ministry of water resources estimated the economic damage at 14bn yuan (£400m).

The deaths occurred when people were washed into fast-flowing rivers that burst their banks, or when mudslides buried homes. As well as the confirmed dead, another 86 people were missing.

The emergency services have upgraded their threat assessment as the National Meteorological Centre warned of more downpours in the days ahead. “The scope and intensity of the rain have increased,” it said on its website. Some areas are forecast to receive 200mm (nearly 8in) of rain.

The state council, China’s cabinet, has dispatched a team to co-ordinate the relief effort. The People’s Liberation Army has joined firefighters and police in a mass evacuation involving boats and helicopters. Transport links have been severed in many areas, due to road damage, flooded railway lines and the danger of travelling in fierce storms. Hundreds of flights have been cancelled. Newspapers have run pictures of elderly people being carried on the backs of their children or grandchildren, wading through the flood waters. Families have taken refuge in public buildings.

Food supplies – already hurt by the earlier drought – will take a further hit. The government estimates that 500,000 hectares (1.24m acres) of crops have been affected. Farmers have been salvaging what they can.

Southern China experiences flooding almost every summer, but the Beijing climate centre says extreme weather events have increased in recent years, with droughts becoming longer and rain falling in more intense and damaging bursts.

Jonathan Watts in Beijing - guardian.co.uk