"If the provincial councils go about doing this kind of work, we will have to take a closer look at the provincial councils system," Opposition leader Nimal Siripala de Silva said, while accusing the pro-LTTE diaspora for being behind the resolution.
He said the resolution threatened Sri Lanka's national security.
The resolution this week demanded the UN High Commissioner for Human Rights to comprehensively investigate and report on the charges of genocide of Tamils in its submission to the UN Human Rights Council which is scheduled for March.
This will also upset President Maithripala Sirisena's policy for reconciliation in the country. They must withdraw the resolution, he stressed, adding the new Sirisena government has expressed disappointment with the resolution.
Analysts say the resolution has dampened the spirit of reconciliation demonstrated by the Tamil National Alliance leaders in attending Lanka's 67th day of independence celebrations early this month. It was the first that time Tamil leaders had attended a national independence day ceremony since 1971.
Sirisena has announced several measures to try and achieve reconciliation with the Tamil minority, seen as a departure from the hardline adopted by his predecessor Mahinda Rajapaksa.
Sri Lanka has been subject to three UNHRC resolutions in 2012, 2013 and 2014 over alleged rights abuses by government troops during the last phase of the war with the Liberation Tigers of Tamil Eelam.
The last one prescribed an international probe into the alleged rights violations.
According to UN estimates, more than 40,000 civilians were killed in Lanka during the final phase of the conflict that ended in 2009. The Sri Lankan government disputes the UN figure.