Home Affairs Minister Peter Dutton has hit back at the former Australian Border Force (ABF) commissioner Roman Quaedvlieg, telling Parliament he was "discredited and disgraced".

Key points: Home Affairs Minister Peter Dutton used parliamentary privilege to lash out at Roman Quaedvlieg

Home Affairs Minister Peter Dutton used parliamentary privilege to lash out at Roman Quaedvlieg He accused Mr Quaedvlieg of "grooming a girl 30 years younger than himself"

He accused Mr Quaedvlieg of "grooming a girl 30 years younger than himself" Mr Quaedvlieg was sacked as Border Force commissioner earlier this year after helping his girlfriend get a job

Federal Labor has been pressing Mr Dutton about the granting of visas to two au pairs.

In Parliament on Tuesday the Opposition also asked whether the Minister played a role in getting an ABF job for a former police colleague and friend.

Mr Dutton said that officer was a decorated and distinguished officer with more than 20 years' service with the Queensland police, arguing the employment process was completely based on merit.

And he told Parliament: "This smear is coming from the former Australian Border Force commissioner, a man who was, as commissioner, sacked from his position."

"He was a man who had groomed a girl 30 years younger than himself," Mr Dutton said.

Mr Quaedvlieg said Mr Dutton's attacks on his "character, reputation, motives, integrity and mental health appear to have arisen" because he made submissions to a Senate committee.

"It is extraordinary behaviour from a Cabinet minister to pre-emptively impugn the character and reputation of a witness attempting to engage properly in a parliamentary process," Mr Quaedvlieg said.

He described the reference to "grooming a girl" as disgusting and offensive, and he called on the Minister to formally withdraw the comment.

Mr Quaedvlieg also tweeted a response describing Mr Dutton's statement as "curious, stuttering, rambling" comments.

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Later in the evening, Mr Quaedvlieg tweeted that he had written to the Speaker about Mr Dutton's comments, saying "this is not what [parliamentary] privilege is for".

Mr Quaedvlieg has made two submissions to the Senate inquiry that is investigating Mr Dutton's actions involving the visas for the au pairs.

He has been criticised for including inaccurate dates in a submission and has since conceded he made a mistake with the dates.

He said the only "logical conclusion" was there was a third case yet to come to light.

Prime Minister Scott Morrison said he was disappointed by Mr Quaedvlieg's comments, which he said completely lacked credibility.

"I worked with Roman when I was the immigration and border protection minister," Mr Morrison told the ABC's 7.30 program.

"I'm disappointed that he's made these false claims and sought to sledge the character of Peter Dutton."

Mr Quaedvlieg was sacked from the ABF commissioner position earlier this year after helping his girlfriend get a job within Border Force.

He had earlier stepped aside so an investigation into his conduct with a younger female staffer could be completed by the Prime Minister's department.

Peter Dutton (right) made Roman Quaedvlieg the first Australian Border Force commissioner. ( AAP: Dan Peled )

Dutton describes Quaedvlieg as 'Labor's Godwin Grech'

Mr Dutton told Parliament Mr Quaedvlieg was providing information to Labor, which the Opposition was using as the basis for parliamentary questions.

"As it turns out, his executive officer now is a senior adviser to the Leader of the Opposition," Mr Dutton told the House of Representatives.

"So all of this muck that has been thrown — I note that Mr Quaedvlieg doesn't turn up in person to the Senate inquiry, I suspect because he doesn't want to be cross-examined.

"So what he does is puts out these fictitious bits of information and salacious detail that he can't back up.

"He has been proved already to be discredited. He is somebody the Labor Party should not rely on."

Mr Dutton compared the former commissioner to the ex-Treasury official Godwin Grech, who gave information to then-opposition leader Malcolm Turnbull that turned out to be untrue.

"It is clear to me that Roman Quaedvlieg is your Godwin Grech," Mr Dutton said.

"These attacks of a personal nature are only based on the lies and information of an individual."