External affairs minister GL Peiris told the UN Human Rights Council at the rights body's ongoing sessions in Geneva in response to a report on Sri Lanka submitted by UN Human Rights Commissioner Navy Pillay.
"The recommendations contained in the report are arbitrary, intrusive and of a political nature," Peiris said.
Peiris said Sri Lanka was against country-specific action but had proactively engaged the UN system in cooperation and dialogue.
Pillay had called for setting up an international inquiry mechanism to probe allegations of rights abuses and accountability for international humanitarian law violations.
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The UN rights chief's report was a preamble to the US- moved resolution, to be voted at the end of the month. The draft resolution backed Pillay's call to set up an international war crimes inquiry.
Peiris said Sri Lanka was rejecting both the US-moved resolution and Pillay's report in its entirety because they are "fundamentally flawed".
This will be the third UNHRC resolution on Sri Lanka. Both previous resolutions were adopted with India's support.
The country has faced accusations of an estimated 40,000 civilian killings during the final phase of the war against the LTTE in 2009.
Peiris said civilians may have been killed due to dropping of artillery rounds fired by ill-trained LTTE gunners.