Thousands of people have been forced to evacuate the days-long rainstorms across swathes of northern China this week.

Chinese President Xi Jinping urged authorities late Monday to plan for worst-case scenarios and rush the relocation of residents of flood-threatened areas.

"The latest round of heavy rainstorms has left 30 people dead in Beijing as of midnight Monday," state news agency Xinhua said, citing the city's municipal flood control headquarters.

Local outlet Beijing Daily said on social media that "continuous extreme heavy rainfall caused major disasters".

The death toll was highest in Miyun, a suburban district northeast of the city centre, it said.

Dozens of roads have been closed and over 130 villages have lost electricity, Beijing Daily said.