Sri Lanka's military has banned foreigners from travelling to the country's former war zone during a visit there by President Mahinda Rajapakse, officials and diplomatic sources said.

Foreigners were turned back at Omanthai, the army-controlled entry point to the Northern Province, where ethnic Tamils continue to accuse the government of human rights violations since the military crushed a separatist movement there in 2009.

Military officials said on Sunday that the travel ban had been in place since Friday and was in the "national interest".

Among those affected were people of Sri Lankan origin on their way to attend weddings, funerals and religious rituals in Jaffna, the cultural capital of Tamils, the Sunday Times , a UK-based newspaper, reported.

Diplomatic sources said foreign experts working on development projects in the former war zone had also been turned back, despite having permission to work there.

Rajapakse is visiting the Northern Province for the reopening on Monday of a railway line to the provincial capital Jaffna.

He will also chair a meeting to review construction work in the battle-scarred area, where troops crushed Tamil separatists in May 2009 and declared an end to 37 years of bloodshed.

Sri Lanka has repeatedly warned that minority Tamil groups abroad may try to revive the defeated Tamil Tigers, who fought for an independent homeland for the island's main ethnic minority.

However, since the end of fighting in 2009 no attacks have been blamed on the Tamil Tiger rebels, who at the height of their power controlled a third of the country's territory.

The UN has estimated that up to 100,000 people may have been killed in the separatist conflict between 1972 and 2009.

Source: Agencies