Nationalist backbencher Franco Debono's walkout during a parliamentary vote on Monday was a rash move that has put his political career at risk, according to former PN minister Michael Falzon.

"To be in politics, one needs patience and perseverance and not actions such as these - he is risking his political career," said Mr Falzon, who has a more than 20-year political career behind him.

Dr Debono's actions were only going to backfire on his career. "He has to admit that he made a mistake - that he was rash."

Mr Falzon also pointed out that the young MP is a newbie in the game, with less than two years' experience in Parliament.

Mr Falzon's analysis was echoed by former PN candidate and lawyer Georg Sapiano who said that Dr Debono had to clear the air by explaining his actions.

Only issues relating to the ill-health of an MP or that of his family could justify this kind of sudden departure from Parliament before the vote, he said.

If none of these were possible reasons, "anything else will inevitably be considered a personal agenda and I very much hope that this is not the case here," Dr Sapiano said.

During a PN parliamentary group meeting held at Castille on Tuesday, party whip David Agius denied there was any pressure for Dr Debono to resign after his absence.

Although two days have passed since Dr Debono's absence in Parliament, he has since made himself completely inaccessible and could not be reached in any way for his comments.

He did not turn up at his office in Valletta and switched his mobile phone off and on at various intervals without answering any calls.