Colombo  - UN Humanitarian Affairs chief Sir John Holmes arrived in Sri Lanka to assess the needs of tens of thousands of civilians who fled rebel-held areas or remain trapped in the fighting, officials said Sunday.

Holmes planned to visit refugee camps in Vavuniya, 254 kilometres north of the capital, populated by more than 150,000 civilians who fled the north-eastern conflict zones.

His two-day visit came in the wake of military operations aimed at rescuing civilians trapped in an 8-kilometer narrow coastal area in the Mullaitivu district, 395 kilometres north-east of the capital.

Fighting continued overnight between troops and rebels in the area while the number of civilians leaving the area had dwindled over the past two days.

A medical doctor in the rebel-held area said Saturday that the area was facing an acute food and medicine shortage.

The government estimates that the number of civilians in the area at around 20,000, but other sources said the figure could be around 40,000.

Human Rights Minister Mahinda Samarasinghe told Holmes the government hoped to discuss UN involvement in the post-conflict phase of rehabilitation of civilians and re-integration of ex-combatants into society, The Sunday Times reported.

"The displaced people will have to be rehabilitated, and ex combatants reintegrated to society. We also need to resettle the displaced people and provide them a livelihood with essential infrastructure facilities. In all these areas we believe the UN can be our partner," Samarasinghe said.

The military says it is in the final phase of a major military operation to crush the Tamil rebels of the Liberation Tigers of Tamil Eelam who have been fighting for an independent homeland for minority Tamils in the north and east of the country for the last 25 years. (dpa)