Anguished Pakistanis are searching remote areas for bodies swept away by weekend flash floods as the death toll has reached 277.

Heavier than usual rains and sudden cloudbursts during this monsoon season kill more than 300 people in recent days.

Pakistan has received higher-than-normal monsoon rainfall this year, triggering floods and mudslides that have killed more than 540 people since June 26.

Pakistan has issued a flood alert for some southern districts, warning of torrential rains, as rescue teams continued searching for missing people in the northwest, where severe floods have killed hundreds over the past week.

A deluge of rain triggered floods and landslides, sweeping people away and flooding and destroying homes, officials said.

Severe monsoonal flooding has caused widespread devastation across Pakistan, destroying homes and sweeping away entire villages.

Pakistani authorities are defending their response to flash floods that killed more than 200 people in a single northwestern district this week.

Pakistan has been grappling with widespread torrential rains in almost all parts of the country that have wreaked havoc and left over 700 people dead and hundreds injured. The deluge crippled the already dilapidated infrastructure, damaging houses, roads, and commercial centres.