The Australian ambassador to Sweden has written to the country's justice minister seeking assurances that Julian Assange, the WikiLeaks founder, would be treated justly under Swedish and international law, should he be extradited there.

Assange, an Australian citizen, is currently fighting extradition from Britain to Sweden over allegations of rape, sexual assault and sexual molestation made by two women in August last year, which he denies. He will learn within days whether his attempt to resist the European arrest warrant has been successful.

His letter to Sweden's minister for justice, Beatrice Ask, ambassador Paul Stephens writes, is to convey the Australian government's "expectation that, should Mr Assange be brought into Swedish jurisdiction, his case would proceed in accordance with due process and the provisions prescribed under Swedish law, as well as applicable European and international laws, including relevant human rights norms".

He does not state what reasons, if any, Australia might have for seeking such assurances.

Assange's lawyers argue that the conduct of the Swedish prosecutor has been "illegal and/or corrupt" in confirming his identity to the press against Swedish custom for accused sex offenders, and issuing a warrant without charge. The Swedish custom of hearing evidence in sex abuse cases in private is, they say, "a flagrant denial of justice".

They also argue that extraditing the Australian to Sweden would be a breach of his human rights, suggesting this would make more likely his onward extradition to the US, where a number of politicians have called for his imprisonment, or worse, over WikiLeaks' publication of leaked US embassy cables. Such a move would carry a "real risk" of Assange being confined in Guantánamo Bay or facing the death penalty, according to a skeleton argument released last month by his legal team.

Assange will learn his fate on Thursday, when chief magistrate Howard Riddle will deliver his judgment on the extradition warrant. The magistrate has already spoken of the strong likelihood of an appeal from one side or the other, whatever his judgment.

Earlier this month Assange, who is currently on bail in the UK, appealed to the Australian prime minister, Julia Gillard, to "bring me home". "There have been outrageous and illegal calls to have me and my staff killed, clear cases of incitement to violence," he said in a video message to supporters in Melbourne. "Yet the Australian government has condoned this behaviour by its diplomatic silence."

The Swedish justice ministry declined to comment on the Australian ambassador's letter, saying only that the judiciary is independent and the established norm is that ministers never comment on ongoing court cases.

Speaking to the Guardian earlier this month, Ask said there had been no political influence on any of the decisions taken by Swedish prosecutors in the Assange case. "Meeting the law, each one of us is worth as much as one another. That's the whole principle of justice, that the law works in the same way whoever breaks it."

The government had had no discussions with the US regarding Assange's case, she said, but she did not believe that the conduct of WikiLeaks in leaking the cables had been contrary to Swedish law. "People can have opinions about what is in the information, but Swedish regulations on freedom of speech and press are very liberal … the publisher is not liable."