Unicef will help immunise children against measles in the tsunami-hit areas of Tamil Nadu and Kerala as part of a week-long operation.

The campaign will cover 15,000 children in Kerala and 100,000 in Tamil Nadu.

"Measles is a deadly threat to children living in crowded camps," Marzio Babille, Unicef's chief of health in India, said in a statement Sunday.

"It spreads quickly, killing children or severely weakening their immune systems," he said. "The children become too weak to fight off other diseases, leading to more deaths. It's a vicious cycle."

The immunisation drive, to be held in 11 districts in Tamil Nadu and three in Kerala, will be organised by the departments of public health of the two states and the Indian government with support from the WHO, the statement said.

Unicef is also supporting the Tamil Nadu government to do a health assessment in the hard-hit districts, it said.

The statement said Unicef has already distributed 70,000 sachets of oral re-hydration solution (ORS) and a total of 2.02 million sachets will be made available to the state.

Forty vans carrying 120 communication staff are criss-crossing relief areas in Cuddalore, Nagapattinam, Kanyakumari and Pondicherry to distribute and demonstrate the use of ORS.

While there were some cases of diarrhoea at the camps, no major outbreak was reported, said the statement.

As a precautionary measure, however, Unicef plans to provide Tamil Nadu with two "cholera-kits" with drugs and materials to treat up to 1,300 people in the event of an outbreak, it said.

Over 600,000 people are housed in hundreds of relief camps across the tsunami-hit regions. The government has put the toll in the tsunami disaster at 8,955, with 3,872 still missing.