The United Nations has suspended Sri Lankan troops from peacekeeping duties after Colombo ignored repeated warnings and appointed a general accused of war crimes to head its army.

The UN and several Western nations expressed concern over the promotion of Maj Gen Shavendra Silva last month despite the allegations against him.

“In light of this appointment, the UN Department of Peace Operations is therefore suspending future Sri Lankan Army deployments...,” Deputy UN spokesman Farhan Haq told AFP in New York.

“A Sri Lankan Army unit and individual officers currently serving with UN Peacekeeping will thus be repatriated, beginning next month, in accordance with their rotation dates and will not be replaced by Sri Lankan personnel,” Haq said.

In Sri Lanka, the foreign ministry said its secretary, Ravinatha Aryasinha, will meet with the Department of Peace Operations on Friday.

Aryasinha is scheduled to “discuss this matter with the Under Secretary General of the UN Department of Peace Operations”, the ministry said in a statement.

Some 490 Sri Lankan troops are currently deployed for peacekeeping operations in Mali, Lebanon and Sudan. Two Sri Lankan soldiers were killed in a mine attack in Mali this year.

Human Rights Watch welcomed the UN decision, saying it “sends a strong signal to governments that sweeping suspected war crimes under the carpet will not go unnoticed by the world body”.

President Maithripala Sirisena promoted Silva as the new army chief brushing aside international outrage over his appointment.

Silva has been accused by the UN of committing war crimes during the final stages of Sri Lanka's separatist conflict, which ended in May 2009.

The 55-year-old general has dismissed the allegations against him while praising Sirisena's “courageous decision” to give him the top job despite intense foreign pressure.

The government has also rejected as “unwarranted and unacceptable” the avalanche of international criticism over Silva's ascension to the top job.

UN rights chief Michelle Bachelet said at the time she was “deeply troubled” by Silva's appointment. The US embassy in Colombo described allegations of gross human rights violations against Silva as “serious and credible”.

Sri Lanka's successive governments have resisted calls for an independent investigation into the conduct of troops during the final months of the 37-year conflict, in which an estimated 100,000 people were killed.