"As of midday on July 31, some 44 people have died and nine are still missing as a result of the disasters across the whole of Beijing," top city official Xia Linmao told a news conference.

"Between July 23 and 29, Beijing suffered extreme rainfall," he said, adding they had caused "significant casualties and (other) losses".

Out of those deaths, 31 took place at an "elderly care centre" in the town of Taishitun in the northeast of the city, Xia said.

Those still missing are local officials working on search and rescue, he added.

"On behalf of the municipal party committee and the city government, I would like to express deep mourning for those who have regrettably lost their lives, and profound condolences to their relatives," he said.

Swathes of northern China endured deadly rains and floods since last week that forced the evacuation of tens of thousands.