The Labor Party is pushing for another investigation in the Senate on the issue of European au pairs involving Peter Dutton, as the Interior Minister raises a public dispute with his former head of the border force.
Former Australian Border Force Commissioner Roman Quaedvlieg sent a letter to the Senate committee after Wednesday's initial investigation, alleging that Mr. Dutton's chief of staff, Craig Maclachlan, called him for help in June 2015.
Mr. Dutton has labeled the letter "completely false and even fabricated."
Labor Senator Murray Watt believes that another public hearing is needed to get to the bottom of the saga.
"These latest revelations and contradictory evidence mean we need to have another audience," he told ABC radio on Friday.
"It's very typical of Peter Dutton, when he's under pressure, to start throwing mud at other people."
Government Minister Mathias Cormann said the accusations by the former head of ABF contained important inaccuracies in the facts.
"Mr. Quaedvlieg is obviously not a credible witness," Senator Cormann told Sky News.
In the letter, Mr. Quaedvlieg said that Mr. Maclachlan told him that "the boss's partner in Brisbane" had a problem with a possible au pair who had been arrested at the airport.
But Dutton said that Mr. Maclachlan did not work for him until October 2015.
Mr. Quaedvlieg rejected the claim that he fabricated evidence, indicating that he would reconcile the "anomaly" in the dates and that he did not intend to discuss the facts through the media.
Senator Watt says there are 14 incidents involving tourist visas where the Interior Minister intervened. It calls for both men to appear before the committee's investigation.
Mr. Dutton overruled his department's decision to deport the woman and granted him a visa to stay in the country, despite his original plans to work for a former colleague of Mr. Dutton's Queensland police.
In an explosive rebuttal of Mr. Quaedvlieg's evidence, Mr. Dutton questioned his mental health in question and said he was bitter about losing his job for misconduct.
Mr. Quaedvlieg was dismissed from his post after helping his girlfriend get a job at the Sydney airport.
"I urge Dutton to desist from personal attacks and slander about my actions, motivation, integrity, reputation and mental health," Quaedvlieg said.
Dutton faces questions about whether he cheated on parliament by saying there was no personal connection between him and his former police colleague.
Dutton has said he had not spoken to his former police colleague for 20 years, but the man did call his office for help with the au pair case.