A promient dissident from the Soviet state of Georgia, whose surprise testimony helped convict two U.S. newsmen of civil slander last year, has been pardoned by Soviet authorities and returned home free from exile, Washington Post correspondent Kevin Klose reported.

The official Soviet press agency Tass announced the pardon of Zviad Gamsakhurdia, 40, who had already served a shortened prison term and was in exile reportedly in the northern Caucasus. Gamsakhurdia, a writer who once openly called for Georgia's withdrawal from the Soviet Union, pleaded guilty to anti-Soviet agitation during his own trial in May 1978.

His confession of guilt, televised nationwide at the completion of the trial, stood at the center of a subsequent Soviet civil suit against Craig Whitney of the New York Times and Harold Piper of the Baltimore Sun. The suit put further strain on tense U.S.-Soviet relations. Whitney and Piper, in their dispatches, quoted relatives and friends of the one-time dissident as questioning the authenticity of Gamsakhurdia's confession.

The state television committee sued the correspondents charging they had slandered its reputation. The newsmen, calling the proceeding a political reprisal, refused to participate in the ensuing trial at which they were found guilty and ordered to print a retraction and pay a fine.

In the dispatch Tass said Gamsakhurdia "looked fresh and cheerful" when interviewed at home by a Soviet correspondent, amd it quoted him in a fresh recantation of his earlier dissidence.

"In the time since the trial, I had ample time to be alone with myself and reflect on my past, to see ever more clearly how wrong was the road I had taken when I disseminated literature hostile to the Soviet state . . .

"Bourgeois propaganda seized upon my mistakes and created a hullabaloo around me, which causes me pangs of remorse. I have realised the essence of the pharisaic campaign launched in the West, camouflaged under the slogan of 'upholding human rights.'"