Finance Minister Tonio Fenech has lambasted the Labour Party for "mounting an attack" and pressuring him to resign.
"My position is determined by the Prime Minister not (Opposition leader) Joseph Muscat," he told the press this evening when questioned during a video-conference from Brussels.
Dr Muscat on Monday said Mr Fenech's position was untenable and if he does not resign, the Prime Minister should sack him.
But Mr Fenech said it was Dr Muscat who should be answering questions about whether he was breaking his own code of ethics for party journalists.
"Joseph Muscat in this situation is acting as a prosecutor, judge and jury. I think he must decide what he is," Mr Fenech said.
"I have had many opportunities to rebut what he said. But the Labour Party decided it should mount a whole attack in my regard. I believe that when they have nothing to attack a person with - we're used to it now - the Labour Party throwing mud."
He said Dr Muscat showed he was no different from his predecessor. Instead of making sure his journalists followed the party's code of ethics, he was breaking them himself, Mr Fenech added.
Dr Muscat said he believed Mr Fenech should resign because of the recently-tabled VAT department audit report, which revealed a "grave risk" of fraud, and the guilty plea filed by a former member of Mr Fenech's secretariat, Noel Borg Hedley, 67, of Gżira, who admitted to bribery charges in court last week.
"He was involved in one error of judgement after another and has to go. His position is indefensible and it cannot be described in any other way than incompetence," Dr Muscat said, adding that the Prime Minister was acting as his political bodyguard.
Mr Fenech last week listed measures taken since the government-ordered audit of the VAT Department was carried out. He also distanced himself from Mr Borg Hedley, with his spokesman saying the minister was not involved in any way in this case. Mr Fenech became aware of the allegations on November 5 last year and immediately referred the case to the police.