WATCH | Man trapped in car rescued from powerful China floodwaters

A man trapped in his car in strong gushing floodwaters in China was rescued by firefighters while other people were evacuated from their homes in the capital as torrential rains followed Typhoon Doksuri, state television reported.

Beijing and nearby cities stepped up rescue efforts on Tuesday after rains and floods brought by remnants of Typhoon Doksuri disrupted services and food supplies and claimed 20 lives in one of the worst storms to hit northern China in more than a decade.

Beijing's Fangshan district said it would deploy helicopters to drop food, drinking water and emergency supplies to villages in mountainous areas that have been cut off.

In nearby Tianjin, where rain has become intermittent, 35,000 people have been evacuated from homes and the local government fortified river banks and stepped up the inspection and repairs of power, water and communications lines.

Food delivery giant Meituan added staff and extended delivery times as orders for vegetables, meat and eggs rose 50% on its app and overall shopping increased 20%, media reported.

The death toll in Beijing rose to 11 on Tuesday with 13 people missing. The city government said rainfall over the past few days had surpassed levels seen in July 2012, when Beijing was hit by what was then the strongest storm since the founding of modern China, receiving 190.3mm of rain in one day and affecting more than 1.6-million people.

President Xi Jinping demanded thorough search and rescue efforts for those missing or trapped, instructing authorities to minimise casualties and restore living conditions to normal as soon as possible, state media reported. In Hebei province, nine people died and six were missing.

Tsai Ing-wen, president of democratically governed Taiwan, which China claims as part of its territory, sent condolences, her office said, a show of cross-strait sympathy reserved for major disasters.

China's finance ministry announced it would allocate 110-million yuan (about R271m) for rescue work in the Beijing-Tianjin-Hebei region.

Doksuri weakened as it rolled inland and dumped non-stop precipitation in northern cities over a few days. Authorities have warned risks of further floods and other geological disasters remained.

Localised thunderstorms and strong winds were forecast on Tuesday for Beijing, Tianjin and Hebei, state broadcaster CCTV said, as the rain continued into a fourth day.

Rivers have swollen to dangerous levels, prompting Beijing to use a flood storage reservoir for the first time since it was built 25 years ago. As of Monday night, China's capital city had sealed off more than 100 mountain roads and evacuated more than 52,000 people from their homes.

Several subway lines in the capital, including trains in western suburbs, were suspended on Tuesday. Beijing's Mentougou district in the west saw dramatic damage a day before after torrential rains turned roads into rivers, sweeping cars away.

Nearly 400 flights were cancelled on Tuesday and hundreds delayed at Beijing's two airports, tracker app Flight Master showed.

Beijing recorded an average of 260mm of rainfall from Saturday to early Monday, with the Changping Wangjiayuan reservoir logging the largest reading at 738.3mm.

In Hebei, precipitation from Saturday to Monday at one local weather station totalled more than the amount normally seen over half a year, with rainfall amounting to 1,003mm for the three-day period. Precipitation in the county where the station is located averages 605mm a year.

Further west in Shanxi, 42,211 people in the province had been relocated by Monday.

Doksuri swept through coastal Fujian last week, taking a 14.76-billion yuan (about R37bn) direct economic toll on the southeastern province and affecting almost 2.7-million people, with close to 562,000 evacuated from homes and more than 18,000 houses destroyed, state media reported.