An au pair is a person under 30 who travels abroad for a temporary period and lives with a host family. They generally receive free board, meals and spending money in exchange for childcare and light housework duties. AAP understands the woman made a phone call to a contact while she was detained at the airport and was "quickly" granted a new visa that allowed her to enter Australia lawfully. A document tabled in Parliament shows the woman was granted a tourist visa (subclass 600) after Mr Dutton used his ministerial discretion to intervene in the case. Home Affairs Minister Peter Dutton won't say why he used his ministerial discretion to grant a visa to an au pair, whose eVisitor visa was cancelled at Brisbane Airport in 2015. Credit:Alex Ellinghausen "Having regard to this person's particular circumstances and personal characteristics, I have decided to exercise my discretionary powers ... as it would be in the public interest to grant this person a visa," the parliamentary document says.

"I have decided that as a discretionary and humanitarian act to an individual with ongoing needs it is in the interests of Australia as a humane and generous society to grant this person a [visa]." An immigration official familiar with the visa cancellation process at the airport was "very surprised at this unusual set of events". "It is hard to see how the grant of the new visa ... was genuinely in the public interest," the source told AAP. "It is not very common for visas to be granted at the border after the visa a person arrived on is cancelled." The source said that, usually, such people were put on the next available flight home.

Analysis of ministerial discretion statements for 2015 tabled in Parliament shows the bulk of these visas are granted to asylum seekers requiring bridging or temporary humanitarian visas or former residents returning to Australia. A former department official told AAP under the ministerial discretion powers "the minister is God. He can do whatever he likes." Ministerial submissions concerning the au pair did not involve consultation with the department secretary nor the head of customs. Mr Dutton has declined to explain why it was in the public interest to grant a visa to the woman and refused to shed light on her "ongoing needs". Mr Dutton has denied he knew the au pair and that she worked for him or his family. The minister and his wife, Kirilly, have three young children.

Mr Dutton again rejected on Monday having ever acted outside the Ministerial Code of Conduct. "For the wider record, I do not personally know the individuals concerned nor does my wife. They have never been associated with us in any way. We have never employed an au pair," he said. "In my capacity as minister I have intervened on hundreds of cases to either grant or cancel visas." Ministerial standards under the Turnbull and Abbott governments state: "It is critical that ministers do not use public office for private purposes. "Ministers are required to ensure official decisions made by them as ministers are unaffected by bias or ... considerations of private advantage.

"Ministers must ensure they act with integrity - that is through the lawful and disinterested exercise of statutory and other powers available to their office." During the Administrative Appeals Tribunal hearing this month, AAP's lawyer Surya Palaniappan argued the news outlet was not seeking the woman's name and that releasing details that might relate to her employer would not specifically identify her. She said there were strong public interest grounds for disclosing further information from the FOI documents. "Even if the minister has somewhat of an unfettered discretion under the Migration Act, he's nevertheless subject to these [ministerial] standards," she told the hearing. The department's lawyer Brooke Griffin argued that disclosure of personal information of the au pair - including country of origin, employer and conversations with Border Force officials - would be unreasonable because it would breach privacy and make her identifiable.

"There is no evidence whatsoever, before the tribunal, of any personal link between the minister and the [au pair]," she argued. "Nor could it be said that the release of the personal information ... will shed any light whatsoever on the allegation ... at the moment it is mere speculation." Tribunal member Chris Puplick, a former Liberal senator, promised to make a decision on the case "reasonably expeditiously" but gave no time frame. AAP