The UN migration agency IOM on Tuesday said it plans to provide 3,700 shelter repair kits, 5,000 non-food relief item kits and 250 temporary shelters to assist the worst flood-affected areas in Sri Lanka.

The International Organisation for Migration (IOM) said it would seek funding from the UN Central Emergency Response Fund, and the intervention would help an estimated 74,750 people, Xinhua news agency reported.

Heavy flooding, landslides and flash floods have affected some 684,000 people in south and central Sri Lanka. 

The flooding, which is believed to be the worst in over a decade, has left at least 212 people dead and 79 missing.

The IOM's initial rapid assessments conducted last week in some district of Sri Lanka showed that homes and villages were swept away by the flood waters and mud slides.

The IOM cited Sri Lanka's Disaster Management Centre figure of over 2,500 houses which were destroyed and nearly 15,900 houses damaged.

"These numbers could rise as data from damage assessments is compiled in the coming weeks," the IOM said in a statement issued Tuesday.

According to the UN agency, nearly 22,000 people were still sheltering in some 200 over-crowded "safe sites" including schools, temples and churches.

People currently staying in evacuation centres or with relatives and friends were unlikely to be able to return to their homes in the short term, the IOM said.

"People will need shelter and other non-food relief items (when they leave the sites) and we will need to ensure that aid is distributed at the location most useful and appropriate for each affected family," said IOM Sri Lanka Chief of Mission Giuseppe Crocetti.

Earlier on June 2, the UN Humanitarian Country Team launched an Emergency Response Plan seeking $22.7 million to address the critical life-saving and protection needs of 374,000 people in seven districts, targeting four priority sectors, including shelter, food, health and water and sanitation. 

The IOM said it is already supporting the Sri Lankan government and humanitarian agencies with displacement tracking maps generated from its monitoring system updates.