Brian Cowen has defended the Vatican's refusal to deal directly with an investigation into paedophile priests in the Dublin diocese that has shocked the country.

The Taoiseach insisted Rome's effective snub of Judge Yvonne Murphy's inquiry was in keeping with international law concerning diplomatic channels.

Last week's report by the Commission of Investigation into child abuse in Dublin revealed two letters requesting information from the Pope's ambassador, the Papal Nuncio, were not answered.

A similar request to the Vatican Congregation for the Doctrine of the Faith led to a missive to the Department of Foreign Affairs that the commission was not going through the proper diplomatic procedures.

Mr Cowen described as "a matter of regret" that the Holy See didn't give a substantive response but said the Vatican made sure the note was passed on to the commission because they didn't want officials to feel they were ignoring the request.

"My belief is that the commission and the Holy See appears to have acted in good faith in this matter even if the best outcome was not achieved," he said.

Mr Cowen added: "It is of course regrettable that the failure to acknowledge either letter has given rise to the impression that the Holy See was refusing to co-operate with the Commission.

"The approach by the Holy See was consistent with international law, according to which dealings between states should be conducted via the diplomatic channel unless other arrangements are made by mutual consent."

Commission chairperson Judge Murphy had insisted her inquiry was independent of the Government and so was not party to the diplomatic channels.

Justice Minister Dermot Ahern revealed that calls to a special Garda telephone line set up after the Ryan report into child abuse in church and state-run schools has resulted in about 60 cases being actively investigated.