A Sri Lankan parliamentarian who will be a member of a delegation to be sent to the UN Human Rights Council next week, has slammed the UN human rights chief’s report on the island, calling it "an atrocious piece of writing containing lies, half lies and highly contestable statements”.

Sarath Amunugama, a senior former minister who reportedly left for Geneva on Saturday evening, said the Sri Lankan delegation would be meeting with the UN High Commissioner for Human Rights to take up their complaints in person.

The report, released last week, said Sri Lanka had made "virtually no progress" on the investigation of war crimes, and also raised several other issues, including concerns over on-going reports of abduction, torture and sexual violence, institutional failures within the criminal justice system, ongoing harassment of human rights defenders since 2015 and the military’s continued occupation of civilian land.

Read more:  'Virtually no progress' in Sri Lanka on war crimes investigations says UN human rights chief's office

Amunugama though claimed the report was "methodologically incorrect” and contained "totally unwarranted statements”.

His comments come less than a day after Sri Lanka's ministry of foreign affairs agreed to the co-sponsoring of a roll-over UN resolution, which the president, Maithripala Sirisena said he wanted stopped. 

Sirisena said the delegation he would be sending to Geneva would argue that Sri Lanka should be allowed to 'solve its own problems’.