Heavy rains and flooding have forced thousands of people to evacuate in China's southwestern province of Sichuan, with authorities on Sunday urging citizens across the country to brace for more downpours.

In Sichuan, torrential rain since Friday has raised the water levels of 14 rivers, swept away boats and bridges and forced the evacuation of more than 4,600 people, state media reported.

While no casualties have been reported, state media said the rain and flooding have affected more than 120,000 people, forced the cancellation of some train services and caused more than 176 million yuan ($27 million) worth of damage. About 27,000 homes in the city of Bazhong, Sichuan were reported to be without power.

About 900 km (560 miles) to the northeast in the city of Xinzhou, Shanxi province, state media photos showed cars driving through inundated streets. Jincheng city, also in Shanxi province, raised its heavy rain signal to red, the highest level.

On Sunday, China's National Meteorological Centre renewed an alert for rainstorms across the country, forecasting heavy rainfall across wide swathes of north and central China.

The Beijing Meteorological Observatory said accumulated rainfall in the capital is expected to reach 60 to 100 millimetres on average between 5 p.m. on Sunday and 8 a.m. on Tuesday, while the city's flood control authority warned of the heaviest rains in three years.

The city typically records around 600 millimeters of rain annually.

In Hebei province bordering Beijing, heavy rain and thunderstorms left airplanes temporarily unable to take off and land at the airport in Shijiazhuang, the provincial capital, a local news portal reported.