Ms Unefäldt was allowed to enter the country and continued working as an au pair during the month-long trip, unaware of any visa violations.
"[The family] would never even ask me if they thought there was a risk ... We had no problem entering," she said, adding there were no questions or issues at the airport.
Her time spent caring for her employer's three children in Australia passed without incident until Ms Unefäldt took a holiday in Bali without her employer and sought to re-enter the country on the same tourist visa.
It was only at this point that she caught the attention of authorities who questioned her and confiscated her phone.
When they discovered a text message regarding wages for the previous Australian leg of the trip, she was held in the Melbourne Immigration Transit Accommodation Centre for four days before being deported.
Ms Unefäldt, who maintains she did nothing wrong, is now barred from entering Australia for three years.
"They said I had been working illegally [but] all the money was going from a UK account into my UK account ... My income had nothing to do with Australia whatsoever," she said.
Ms Unefäldt said she was told at the airport she "was taking away a job from other Australian girls, that if I didn't come they would have asked an Australian girl instead".
"I was so confused ... It just seems so wrong."
Sue Pember, the founder of Aussie Au Pair Services, told Fairfax earlier this month there were likely "thousands of cases where host families and au pairs are either ignorant of the regulations or knowingly engaging the services of au pairs who do not have appropriate working rights in Australia".
'A free pass'
Mr Dutton used his ministerial powers to spare two other au pairs from deportation in 2015. The matter is now a subject of a Senate inquiry, where the minister's actions are being investigated.
He freed French au pair Alexandra Deuwel from immigration detention after being lobbied by AFL boss Gil McLachlan and granted a visa to Italian au pair Michela Marchisio who was reportedly planning to work for a former Queensland police colleague.
Speaking from the UK, Ms Unefäldt said she was aware the cases were making news in Australia and said there were "double standards".
She said she didn't understand why these women "got a free pass, while I'm still suffering ... This happened months ago and I still wake up crying [thinking about detention]".
"I don't think [Mr Dutton] should choose who should be free or not."
Migration agent Julie Williams said Ms Unefäldt's case showed the contrast between an au pair that had access to the minister and one who did not.
"It is unusual for the minister to get involved in this scenario with the [two] au pairs as there didn't appear to be any compassionate or compelling grounds to do so, or was it in the interest of the Australian public to grant their visa when it was clear that they were going to work, which was in breach of their visa conditions," she said.
Australia does not have a dedicated au pair visa. Instead, individuals need to apply for a Working Holiday Visa (Subclass 417) or Work and Holiday Visa (Subclass 462).
Nicole Kofkin, chief executive of Australian agency Smart Au Pairs, said the Dutton au pair controversy has shone a light on the shortcomings and confusion of the current system.
"The au pair saga has underpinned the need for a regulated au pair program with professional support from approved agencies and a dedicated visa," she told SBS News last week.
Ms Unefäldt has given an evocative account in the Swedish press of what she describes as her inhumane treatment at the hands of Australian authorities while in detention.
"The dream trip ends at Melbourne airport ... Josefin got five minutes to call her parents before driving off and being locked up for an indefinite period," one article said.
Ms Unefäldt told SBS News the individual conducting the interview at the airport was "really aggressive" and "disrespectful".
And, she claims, once she was in detention, "they would not let me know how long I'd be there for ... I spoke to some people who were there for five months ... I was going crazy".
After four days in detention she was taken back to the airport and put on a flight to Sweden.
"I was escorted [through the airport] by three security guards around the public area ... It was like I was a proper criminal," she told SBS News.
"I felt like I'd done something wrong, but I'd just come on holiday with a family."
A spokeswoman for the Australian Border Force said, "while the ABF does not comment on individual cases, it is the responsibility of the visa holder to know and adhere to the conditions of their visa".
The department's webpage on tourist visas does not specifically address rules around working for an overseas employer while in Australia but it says "you must not work in Australia on this visa".
The spokeswoman said Ms Unefäldt should have been on the Working Holiday Visa (Subclass 417).
"Non-citizens who have previously breached their visa conditions, especially the 'no work' right condition, may have their visas cancelled upon arrival in Australia and may face removal."
Asked about Ms Unefäldt's four days in detention, she said, "non-citizens who are refused immigration clearance are removed as soon as practicable".
"[The ABF] takes claims regarding the professionalism of our officers seriously and we have well-established processes in place to review the actions of our officers if a complaint is made".
"We are not aware of any complaint regarding the actions of our officers in this matter."