Dr Azharul Islam Khan, a doctor at Bangladesh's biggest diarrhoea hospital, said the clinic was seeing around 800 new patients a day.

'We're treating the highest number of patients in the pre-monsoon season during our 45 years in existence,' Dr Khan, of the International Centre for Diarrhoeal Disease Research, said.

'The situation is very grim and reaching epidemic levels in Dhaka and its outskirts. An acute crisis of water and unusually prolonged heat wave are to blame for such a severe outbreak.'

Sixteen people have died of diarrhoea-related illnesses and the hospital has treated more than 40,000 patients since the beginning of March, a hospital spokesperson said.

Temperatures in Dhaka reached 42.2 deg C on Sunday, the highest in 14 years, according to weather officials, with no rain forecast for the next week. -- AFP