COLOMBO (AFP) - Sri Lanka's president has bowed to international pressure and relinquished the defence ministry's authority over the police department, an official said on Friday.

President Mahinda Rajapakse has created a new ministry for law and order, and placed it in charge of the 80,000-strong police which had been overseen by the defence ministry for the past nine years.

"The president has issued a gazette notification creating the ministry of Law and Order which will be responsible for the police department," the President's spokesman Mohan Samaranayake said.

There was no government explanation for setting up the new ministry, but an official source who declined to be named said the move was in line with the recommendation of a panel to improve the island's rights record.

The panel, which probed the final stages of the island's decades-long Tamil separatist war, recommended in Nov 2011 that the police department be de-linked from the defence ministry. This was strongly backed by rights groups and the international community.

The latest government move comes ahead of a visit to the island by the United Nations human rights chief Navi Pillay following two Human Rights Council resolutions censuring the island over its rights record.

Sri Lankan troops declared an end to 37 years of ethnic war after wiping out the leadership of the Tamil Tiger rebels in May 2009.

Sri Lanka has resisted international pressure for an independent investigation into war crimes despite what the UN calls "credible allegations" of up to 40,000 civilians killed in the final battles in 2009.

Instead it has conducted a number of its own probes into disappearances and extrajudicial killings during the conflict, which have resulted in few prosecutions or convictions.

Sri Lanka has maintained its forces did not kill civilians while battling Tigers who were known for suicide bombings.