Nair also alleged that though he had brought this to the notice of Home Minister Thiruvanchur Radhakrishnan, no step had been taken on his complaint.
Radhakrishnan, however, denied the NSS leader's charge.
"Tapping phone conversations is illegal and violation of human rights," Nair told reporters at the NSS headquarters at Perunna near here.
An influential community outfit, NSS, has of late, been strident in its attack on the Oommen Chandy government alleging that the interests of the majority community had been neglected by it, a charge denied by the chief minister.