Eight people died after flash floods hit a river in India's eastern state of West Bengal on Wednesday in the latest incident of heavy seasonal rain causing havoc in South Asia.

The death toll from monsoon flooding in Pakistan has reached 1,061, according to the latest figures released by the country's disaster management authority, even as Islamabad continues to seek international aid.

Floodwaters inundated more of Bangladesh on Tuesday.

The death toll from flooding and landslides triggered by heavy monsoon rains in India climbs to 127, officials say, with rescuers searching for dozens more missing.

Heavy monsoon rains continue to lash parts of India's financial capital Mumbai.

Rohingya refugees kept on a Bangladeshi island fear of being exposed to torrid climate during the looming monsoon season and having to put up with "inadequate" health and educational facilities, HRW says in a report.

Thailand reports at least five dead after a flash flood brought by seasonal monsoon swept through.