Novak Djokovic still faces uncertainty as to whether he will be free to defend his Australian Open crown, despite his release from detention.

The federal government is now investigating whether the tennis ace incorrectly completed his travel declaration forms upon entry to Australia, with Immigration Minister Alex Hawke still considering whether to intervene and cancel his visa.

The move comes as the Serbian prime minister asked Scott Morrison for more timely information on the status of Djokovic, and sought assurances he would be treated with dignity before the tournament starts next week.

Although Monday court’s ruling overturned the decision to cancel Djokovic’s visa, allowing him to remain in Australia, Mr Hawke still has the power to cancel the visa again under discretionary powers held by the minister.

On Tuesday night, a spokesperson said Mr Hawke was “considering whether to cancel Djokovic’s visa under section 133C(3) of the Migration Act”.

Under that section of the act, the minister can cancel a visa if they are “satisfied that it would be in the public interest” to do so.

“In line with due process, minister Hawke will thoroughly consider the matter,” the spokesperson said.

Immigration Minister Alex Hawke. Photo: AAP

The Australian Open is due to begin on January 17.

A new line of inquiry involves whether the Serbian star made a mistake on forms he filled out upon entry to Australia.

Newly released documents showed he answered “no” to questions on his Australian travel declaration forms about travelling internationally within the previous 14 days.

However, the Monte Carlo-based player was photographed playing tennis in Serbia on Christmas Day, and training in Spain on January 2 – both within the 14-day window.

The declaration notes that giving false or misleading information is a serious offence, while civil penalties are also possible.

Questions still remain about how the Djokovic visa bungle occurred, with differing stories between the Victorian and federal governments, and Tennis Australia.

Victorian Premier Daniel Andrews said it was “entirely a matter for the federal government”.

“The issue of who gets into the country and their vaccination status is not an issue for state governments. I don’t issue visas. The Commonwealth government does that,” Mr Andrews said on Tuesday.

“We have not sought to convince the Commonwealth government to allow anyone else. Quite the opposite.”

The federal Labor Opposition hammered the Coalition over the saga on Tuesday, with shadow home affairs minister Kristina Keneally claiming the government had been made to look “like a pack of idiots”.

“If [Djokovic] gets deported, it does incredible damage to Australia. If he gets to stay, it does incredible damage to our tough border laws and is a real insult to the Australians who did the hard work of lockdowns and vaccination,” she said.

Djokovic and his entourage at centre court in Melbourne late on Monday, after a court overturned his visa rejection.

Opposition Leader Anthony Albanese accused the Coalition of “the grand slam of pandemic failures”.

“This has been botched completely by the Australian government,” he claimed.

“This has caused a great international embarrassment for Australia.”

The ATP, the peak body for men’s tennis, weighed in with a statement on Monday.

It claimed the international incident had been “damaging on all fronts, including for Novak’s wellbeing and preparation for the Australian Open”.

“Complications in recent days related to player entry into Australia have, however, highlighted the need for clearer understanding, communication and application of the rules,” it said.

On Tuesday, Mr Morrison spoke to Serbian leader Ana Brnabic.

Serbian broadcaster RTS said Ms Brnabic asked Mr Morrison to ensure Djokovic was treated with dignity following Monday’s Federal Court visa ruling.

“The [Serbian] prime minister especially emphasised the importance of the conditions for training and physical preparation for the upcoming competition, considering that Novak Djokovic was not allowed to train in the previous days, and the tournament in Melbourne starts this weekend,” RTS reported.

“The prime minister also asked [Mr] Morrison to be in direct contact in the coming days and for all information to be exchanged directly between the government of Serbia and the government of Australia.”

Mr Morrison’s office described the call as “constructive”.

“The PM explained our non-discriminatory border policy and its role in protecting Australia during the COVID-19 pandemic,” an Australian readout of the call said.

Last week, Mr Morrison defended the visa cancellation.

He claimed that “rules are rules” and “if you’re not double vaccinated and you’re not an Australian resident or citizen, well, you can’t come”.

That strong endorsement threatens to turn the incident into a political grenade, with either outcome – overruling the court’s decision, or allowing Djokovic to remain in Australia – likely to cause controversy.