Former president and Solidarity leader Lech Walesa must pay 7,500 zloty (3,277 dollars) for calling another former union activist a "cut-throat monkey" and "sick moron," a Gdansk court ruled on Friday.

The court ruled Walesa had defamed Krzysztof Wyszkowski during a TV show in June, 2005, while discussing whether the Institute of National Remembrance should grant Walesa the status of victim of the communist security forces.

Wyszkowski had previously accused Walesa of collaborating with the communist secret police.

Walesa, who was taking part in a debate on education and did not attend Friday's trial, said he would appeal the court's decision, the Polish Press Agency reported. He declined to comment further.

Walesa had previously apologized for the name-calling on his blog, but Wyszkowski said the apology was done in an off-handed, disrespectful way.

A recent book claimed new evidence that Walesa was an informer for Poland's communist-era secret service in the 1970s while working at the Gdansk shipyards, and later as president removed archive documents that implicated him.

The book, published by the Institute of National Remembrance, sparked a long-standing debate on the Nobel Peace Prize-winner's past.

Walesa became an anti-communist hero worldwide after he led a strike at the shipyards against Poland's communist regime in 1980, helping bring down communism at the end of the decade. He was awarded the Nobel Peace Prize in 1983.

Walesa won a 2000 court ruling that said he was not a spy. But opponents, including Polish President Lech Kaczynski, say they know he had worked for communists.

Many see the allegations as tactics used by right-wing politicians for political gain. In a recent survey conducted by the daily Dziennik, 43 per cent said they did not believe the former president worked with the secret police.