In a response to an internal review of the world body released last week, Sri Lanka's External Affairs Ministry said the report "appears to be another attempt at castigating Sri Lanka for militarily defeating" the Tamil Tiger guerrillas, who fought for a separate state in the Indian ocean island nation.
The UN report said the world body's own inadequate efforts to protect civilians in 2009 during the bloody final months of the civil war marked a "grave failure" that led to suffering for hundreds of thousands of people.
The report also accused UN staff in Sri Lanka's capital Colombo of not perceiving that preventing civilian deaths was their responsibility and accused their bosses at UN headquarters of not telling them otherwise.
A separate UN report released last year said up to 40,000 ethnic minority Tamil civilians may have been killed in the war's final months.
The report also accused the government of working to intimidate UN staff, withholding visas of those critical of the government and of planting false allegations against them in the media.
Those accusations against the government drew the rebuke from the Sri Lankan foreign ministry. "While this report is an internal review of the UN's action in Sri Lanka during the terrorist conflict, the ministry's attention has been drawn to certain issues with regard to allegations directed at the government of Sri Lanka, which are regrettably unsubstantiated, erroneous and replete with conjecture and bias," the ministry said in a statement.
It said the UN report did not mention the "intransigence of the LTTE ( Liberation Tigers of Tamil Eelam), which held the people as a human shield, and even shot in cold blood those who tried to escape to gain their freedom".
But contrary to the government's assertion, the UN report was heavily critical of the rebels and accused them of holding tens of thousands of Sri Lankan civilians as human shields and shooting those who tried to escape.
The report was compiled by a committee headed by former UN official Charles Petrie. It investigated UN actions as the quarter-century war between the government, dominated by the ethnic Sinhalese majority, and minority Tamil rebels ended in 2009 in a wave of violence.