Mr. Dutton used parliamentary privilege Tuesday to accuse former Australian Border Force chief Roman Quaedvlieg of "grooming" a younger woman who became his girlfriend.
Quaedvlieg has demanded that he withdraw the "disgusting and offensive" comment, which he said was an accusation of a criminal sexual offense.
However, the prime minister does not believe that the former head of ABF has become a pedophile.
"He has not done that, he has not done it at all," Morrison said Wednesday.
The Minister of Internal Affairs verbally attacked the 53-year-old former ABF chief in parliament after Labor questioned Mr. Dutton over allegations of pressuring two Queensland police officers to secure jobs at the agency.
"(Mr. Quaedvlieg) was, as commissioner, dismissed from his position, a man who had prepared a girl 30 years younger than him," Dutton told parliament.
"He is discredited and disgraced."
Quaedvlieg, who was fired from his post after helping his girlfriend get a job, responded on Twitter.
"Talk to anyone in the community and put the words" prepared "and" girl "together and see where your mind goes, much less a former police officer, let alone to one who has investigated crimes against minors, "Quaedvlieg wrote on Wednesday. .
The prime minister said that Mr. Dutton had been subjected to "false and false" accusations.
"What he has expressed, I think, is a lot of frustration over the false and repeatedly false claims that have come up, and I'm surprised they continue to be informed," Morrison said.
The Special State Minister, Alex Hawke, does not believe that the "preparation" implied that Mr. Quaedvlieg was a pedophile, arguing that Mr. Dutton had responded to a personal vendetta against him.
"It's up to the people in parliament to decide their own language and I understand the frustration that Peter Dutton feels," Hawke told Sky News.
Prime Minister Scott Morrison has criticized the former head of the border force, Roman Quaedvlieg.
But work does not share that understanding.
"He has every right, of course, to defend his decision-making," Deputy Governor Tanya Plibersek told Sky News.
"What he has no right to do is to attack public servants under parliamentary privilege in quite unpleasant ways."
The uprising between the two former Queensland police officers was originally triggered by Mr. Dutton's decision to grant visas to two au pairs detained by immigration.
Mr. Dutton was also accused of pressuring Mr. Quaedvlieg to secure jobs at the ABF for two other former police officers, including one who is now an adviser in his ministerial office.