As of 9:30 a.m. (0130 GMT) 24 flights at Pudong International Airport and 70 flights at Hongqiao Airport, which handles mainly domestic flights, were delayed, it said.

Airports in nearby cities of Hangzhou and Nanjing were closed temporarily following the snow, state media Xinhua quoted flag carrier Air China as saying.

All three runways at Pudong airport, the country's second busiest airport, and the two runways at Hongqiao airport remain open, the operator said in a statement posted on its website www.shanghaiairport.com.

The government had issued earlier on Thursday a heavy snow warning for Shanghai and surrounding regions.

Snow and sleet has hammered a wide belt of provinces across south China, including Zhejiang, Jiangsu, Hunan, Guangxi, Yunnan, Guizhou and Chongqing municipality, cutting power and causing transport disruptions.

Meteorologists are forecasting heavy snow through at least Friday in Chongqing, where the city's Zhoubai airport also was closed due to icy runways, state media said.

The winter weather has disrupted operations at power transformer substations and damaged power lines in eight cities in Yunnan province, with ice on lines as thick as 21 millimetres, Xinhua reported.

In Jiangxi province, closed highways caused traffic back-ups of more than 20 kilometres near Jiujiang city, the news agency said.

Blizzard conditions prevailing in many provinces are expected to spread to Hubei and Anhui provinces within the next 24 hours.

Officials have warned rain, snow and ice could disrupt travel plans for millions who aim to get on the road during the Lunar New Year holiday.

A record 230 million people will travel by rail to their home towns this year, an increase of 12.5 percent over last year, according to local media reports.

he Spring Festival does not officially start until Feb. 3, but many migrant workers and others head home early to beat the crush of travellers.

In early 2008, freezing weather across southern China caused power cuts and transport chaos, preventing many residents from spending the holiday with their families.