Dutton says that deporting the au pair would have been "a bit hard".

Peter Dutton

Peter Dutton says he personally intervened to save a French au pair from deportation because he thought it was "a bit difficult" for a young woman without a criminal record to be expelled from the country.

As immigration minister in November 2015, Dutton intervened to free the 27-year-old from immigration detention after his office was pressured by AFL chief Gil McLachlan.

Dutton, who is now the interior minister, said he weighed the case because of his merit and not because of the person who had referred him.

"I looked at him and I thought it was a bit harsh, there was no criminal record, she agreed that he would not work while he was here," he told the 2GB radio on Thursday.

"As I understand it, she never delayed the visa, did not commit any crime and I thought it was an application of common sense."

Workers have questioned whether donations to the state and federal branches of the liberal party influenced their decision to help a French au pair in the country.

The au pair, Alexandra Deuwel, was returning to Australia to work with Australian pastor Callum MacLachlan, second cousin of AFL chief Gillon McLachlan.

He was originally denied a tourist visa because of concerns that he was planning to work, but Mr. Dutton used his discretionary powers to grant him a visa.

Documents from the Australian Electoral Commission show that Callum's father, Hugh MacLachlan, has donated $ 150,000 to the Liberal party.

Shadow Immigration Minister Shayne Neumann told the ABC on Tuesday that "questions of whether a donor or relatives of the Liberal party have asked the minister to help them should be aired before an investigation in the Senate."