Rescue workers on Tuesday recovered more bodies from a mountain village in northwest Pakistan where flash floods triggered by a cloudburst brought down homes and buildings, bringing the death toll there to at least 20, the local district commissioner said.

The toll contributed to a total of 358 deaths in the floods in Khyber Pakhtunkhwa province since Friday – more than 200 of them in the worst hit district of Buner.

The Provincial Disaster Management Authority says 30 children are among the dead.

A cloudburst is a rare phenomenon where more than 100 mm (4 inches) of rain falls within an hour in a small area, officials say. Authorities have warned of more rains to come in two spells of monsoon until September 10.

In Buner, there was more than 150 mm of rain within an hour on Friday morning. A massive downpour from another cloudburst struck near Gadoon in the mountains of Swabi district, also in Khyber Pakhtunkhwa, on Monday.

District Commissioner Nisar Khan said that as well as the death toll there increasing from 11 on Monday, several residents remained missing from the remote village.

"We are utilising all available resources, including heavy machinery such as excavators, to recover the missing bodies," he said.

The raging flood water came down from the mountains and swept away the houses, he said.

The intense rain has claimed lives and spread destruction in several northwestern districts, with most people killed in flash floods, according to the National Disaster Management Authority.

More relief equipment including tents, blankets, electric generators, pumps, medicine and rations have been sent to the flood-affected areas, the National Disaster Management Authority said on Tuesday.

It said the torrential rains and flooding this monsoon season have killed 695 people across Pakistan since late June.