Convicted US whistleblower Chelsea Manning is likely to have her visa application knocked back by the federal government only days before her speaking tour is due to start.
Tour organiser Think Inc has received a notice of intention to deny the former soldier entry into Australia under section 501 of the Migration Act.
"After a little bit of research, and speaking to our legal counsel, we understand there is potentially an imminent refusal of her visa," Think Inc director Suzi Jamil told the ABC.
Ms Manning, a former army intelligence analyst best-known for leaking more than 700,000 classified military and diplomatic documents, is scheduled to start her Australian speaking tour at the Sydney Opera House on Sunday.
Think Inc is calling on the transgender activist's supporters to lobby new Immigration Minister David Coleman to allow her into Australia.
Late on Thursday, the Australian Lawyers Alliance directed a letter to Mr Coleman pleading for Ms Manning to be granted access into the country.
"Denying her a visa serves no national interest grounds," ALA president Noor Blumer wrote.
"The ALA considers that Ms Manning has generated essential public debate on several important issues."
The Department of Home Affairs said while it does not comment on individual cases all non-citizens entering Australia must meet character requirements set out in the Migration Act.
"A person can fail the character test for a number of reasons, including but not limited to where a non-citizen has a substantial criminal record or where their conduct represents a risk to the Australian community," a department spokesman told AAP in a statement.
Prime Minister Scott Morrison, who held the immigration portfolio in the Abbott government, said it was a "personal" decision for the minister.
Labor foreign affairs spokeswoman Penny Wong believes the government should be transparent about the reasons if Ms Manning is denied entry.
"A more light-hearted response might be that if Chelsea Manning came as an au pair, she might have a better chance of getting in under Peter Dutton," Senator Wong told Sky News.
Amnesty International accused the government of trying to silence Ms Manning.
"By refusing her entry, the Australian government would send a chilling message that freedom of speech is not valued by our government," Amnesty International Australia director Claire Mallinson said in a statement.
Ms Manning is also facing calls to be barred from New Zealand with the centre-right National Party opposition urging the government to decline her visa request.
She was banned from entering Canada last year due to her criminal convictions in the US, but was allowed to speak in Montreal in May.
She is also due to speak in Melbourne on September 7, Auckland on September 8, Wellington on September 9 and Brisbane on September 11.
The National Union of Students LGBTI is planning to stage a protest rally in Sydney on Friday, calling the government's move to block Ms Manning a "blatant attack upon freedom of speech".
