SHANGHAI, Sept 19 (Reuters) - Typhoon Wipha slammed into China on Wednesday, packing high winds and heavy rains, as the financial hub of Shanghai braced for what could be the most destructive storm in a decade.

More than 2 million people were evacuated throughout east China ahead of Wipha, which made landfall in Cangnan county in coastal Zhejiang province with winds clocked at 45 metres per second, state media reported.

President Hu Jintao and Premier Wen Jiabao "demanded that relevant provinces and cities strengthen their guard against the typhoon, increase implementation of defence measures ... and safeguard the lives and safety of the people", in a notice posted on the government's Web site (www.gov.cn).

Shanghai was reeling from heavy winds ahead of the storm. Traffic slowed to a crawl in older areas on Tuesday as flooding reached levels of nearly a metre in some places and some underground car parks flooded.

Financial markets were expected to open according to their normal schedule, but the Shanghai Stock Exchange said it would monitor conditions throughout the day.

The city has halted all construction projects, closed riverside parks and evacuated 291,000 people from low-lying areas.

At least one person has died in the storm, when he stepped in water touched by an electrical wire, the Shanghai Daily reported.

Xinhua said two FIFA Women's World Cup matches originally scheduled for Wednesday in Shanghai and Hangzhou had been postponed to Thursday. The Shanghai match will also be relocated to Hangzhou.

Wipha grazed northern Taiwan on Tuesday, prompting the closure of schools, offices and financial markets.

"A striking feature of Typhoon Wipha is that it was not weakened by crossing the terrain in Taiwan, and its strength is very intense," the China Daily quoted Duan Yihong, deputy director of the National Meteorological Centre, as saying.

However, the Tropical Storm Risk Web site (http://tsr.mssl.ucl.ac.uk/) showed the system weakening to a tropical storm from a Category 3 typhoon in about 12 hours.

Across southeast China, boats had returned to harbour and by Tuesday evening rain was so heavy that some rivers and reservoirs in Zhejiang had risen to warning levels, state media said.

Typhoons regularly hit China, Taiwan, the Philippines and Japan in the summer months, gathering strength from warm sea waters before weakening over land.

Xinhua said on Tuesday Wipha may turn out to be the most destructive typhoon in a decade. Last August, Typhoon Saomai killed more than 400 people and was labelled at the time the strongest storm to hit the country in 50 years.

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