The United Nations' rights chief Navi Pillay, who is investigating allegations of war crimes by Sri Lanka, is the target of a smear campaign by Colombo, her office said Friday.
Pillay's spokesman Rupert Colville said there had been no letup in the "extraordinary array of distortion and abuse" the UN high commissioner for human rights faced from Sri Lankan officials during a fact-finding mission there last month.
"We consider it deeply regrettable that government officials and other commentators continue what appears to be a coordinated campaign of disinformation in an attempt to discredit the high commissioner or to distract from the core messages of her visit," Colville told reporters.
Pillay is probing allegations of war crimes by Sri Lanka, four years after the end of a Tamil separatist war that according to UN estimates claimed up to 100,000 lives between 1972 and 2009.
A military offensive in 2009 crushed Tamil Tiger rebels who at the height of their power controlled one-third of Sri Lanka's territory, but rights campaigners say Sri Lankan forces killed thousands of civilians in the process.
Pillay is a South Africa of Indian Tamil heritage, and during her visit she slammed "deeply offensive" Sri Lankan claims that she was a tool of the rebels.
She called the Tamil Tigers a "murderous organisation" which should not be glorified by the world's Tamil diaspora.
At the end of her mission on August 31, Pillay accused President Mahinda Rajapakse's regime of rising authoritarianism.
Sri Lanka charged Pillay was meddling and overstepping her mandate.
Colville said Pillay's office had on September 12 sent a formal complaint to the government over widely reported remarks by Defence Minister Gotabaya Rajapakse, who is also the president's brother.
Rajapaksa has claimed that Pillay demanded Sri Lanka remove the statue of its first prime minister from Independence Square in Colombo.
"This claim is without a shred of truth," said Colville.
Pillay is scheduled to present a report on her Sri Lanka mission to the UN Human Rights Council on September 25.