400 people are reported to have come down with diarrhoea since cylcone Ami struck Fiji's northern town of Labasa and surrounding areas two weeks ago.
Dr Ami Chandra, the director of the Northern Health Service which includes Labasa and Savusavu hospitals as well as 18 health centres, says 50 people a day are now being treated for diarrhoea.
The water supply has been restored in Labasa but people in outlying areas are still relying on rain water or drinking from streams.
Dr Chandra says the situation is under control.
"We have got our people doing health education through direct contact with the community as well as the mass media and we have got our health inspectorate personal doing spraying and giving chlorine tablets to purify the water."
Meanwhile, 12,000 children are reported to be in desperate need of help to continue their education.
A spokesman for the Save the Children Fund, Irshad Ali, says they've received 70,000 US dollars from a local appeal but much more is needed and they will be asking for overseas help.
The fund plans to supply books and stationery, and help with school lunches and bus fares.