Police in Sri Lanka on Friday arrested 41 people on suspicion of attempting to migrate illegally by boat to Australia, officials said.

The group was arrested in Vakarai, 280 kilometres east of the capital, as they were making preparations to board a boat, a senior police officer in the area said.

Most of them were ethnic Tamils from the former war-affected areas in the northern part of the country, he said.

Police said there has been a sudden increase in attempts by Sri Lankans to migrate illegally to Australia by boat.

At least eight attempts have been foiled during the past two months by the police and navy and more than 150 people have been arrested. Courts have released most of them on bail.

The Sri Lankan Navy has stepped up its surveillance in coastal areas to prevent illegal migration. - Sapa-dpa