Former Foreign Minister Michael Frendo would have resigned if Richard Muscat had not stepped down as ambassador to Ireland last year.

"It was either me or him," he told The Sunday Times.

Dr Frendo said: "I asked him to resign. If he had not resigned I would have sacked him... or resigned myself. Anything else would have been a dereliction of duty on my part."

The clash between the two Nationalist Party stalwarts follows Mr Muscat's claims in an interview last Sunday that Dr Frendo told him to resign because he was "in the way" of his bid to become Commonwealth Secretary General.

Mr Muscat yesterday stood by what he said, saying that not only had Dr Frendo said these words, "but worse still, he meant it and acted on it by forcing my resignation".

Dr Frendo has categorically denied this and reiterated that he had never used this kind of language, "of standing in my way", with anyone in 30 years of political service.

Dr Frendo said he was baffled how Mr Muscat concluded that the Commonwealth bid had anything to do with it.

He admits he was very busy with his campaign at the time and could have mentioned it in the course of the conversation, "but certainly not in relation to his resignation".

The former minister stressed that Mr Muscat's resignation had nothing to do with Malta's candidacy for the Commonwealth post, however much it may make Mr Muscat "feel better about his behaviour by believing he was 'sacrificed' because of it".

Dr Frendo said he was upset that this allegation, which he described as illogical and ridiculous, was featured "unjustly" - depicting him as some callous politician willing to run roughshod over others.

He pointed out that Mr Muscat had failed to inform him of sexual assault allegations against the former ambassador's son for 10 months, and only broke his silence when the story hit the headlines in the Irish tabloids in August last year.

"Imagine being a minister and reading reports in the media which he had hid from you? I never uttered a word about this, but the police actually arrested Richard's son from the embassy residence (in Ireland). This could have sparked a diplomatic incident," he said.

"He was obliged to tell me, his minister, about this - not the Irish Foreign Office. He didn't say a word because he wanted me to renew his post... He never told me or anyone in the ministry. We cannot have ambassadors who act this way.

"I admit I was deeply hurt, and quite furious about Richard's decision to withhold telling me... at a time when he knew I was deciding whether to extend his posting by one year."

The revelations in the newspapers emerged just after Dr Frendo had "stuck his neck out" for Mr Muscat by extending his posting in Ireland when a controversy involving the Voice of the Mediterranean radio station (where there had been allegations of wrongdoing, which were eventually dropped) were still pending.

"If Richard had told just me it would have never leaked out. The matter could have been resolved... It would have never led to this," he said.

"It was very hard for me to take such a decision because I know Mr Muscat well... He put me in an impossible situation. If he had some sense he would have asked me not to renew his post and the story would have stopped there."

In last week's interview with The Sunday Times, Mr Muscat had said he had made a "judgement call" not to inform the Foreign Affairs Ministry because he felt the news would leak out and land in the hands of the opposition.

Yesterday he said: "I was faced with a most delicate situation in my family... The Irish Foreign Office were kept in the loop according to protocol. I was eventually proved right in my judgment when the Irish authorities ruled there was no basis to proceed against my son, and proved the allegations were unfounded."

However, Dr Frendo stressed that the allegations against Mr Muscat's son had nothing to do with the resignation. On the contrary, he was happy no charges were brought against him.

"He (Richard Muscat) is trying to change the parameters. The issue is that there was this incident and the minister was not informed," he said.

Dr Frendo said he tried to sugar the pill for Mr Muscat by, in the resignation letter, suggesting these allegations placed him in an impossible situation to serenely carry out his duties as ambassador.

"The real reason, of course, and he surely knew it, was that he had disloyally and irresponsibly withheld information on an extremely serious matter, breaking all the rules in the diplomatic book on such matters. He seems to have remained in denial about the magnitude of this," he said.

"Rather than playing the victim, Mr Muscat should realise in what political predicament he put others, including me, with his irresponsible action. My only choice was to act responsibly as a minister in the paramount interest of Malta's international reputation and the credibility of our diplomatic service."