CANBERRA, Aug. 30 (Xinhua) -- U.S. whistleblower Chelsea Manning might be denied entry into Australia days before her scheduled speaking tour.

Manning was due to give a speech in an event at the Sydney Opera House on Sunday before moving on to Brisbane and Melbourne, but on Wednesday received notice that the government was considering refusing her entry under section 501 of the Migration Act.

Under section 501, Home Affairs Minister Peter Dutton can "refuse to grant a visa to a person if the person does not satisfy the minister that the person passes the character test."

Manning spent seven years in a military prison after being convicted of leaking 700,000 classified documents to WikiLeaks.

Former U.S. President Barack Obama commuted her 35-year sentence in January 2017, paving the way for her release on May 2017.

The organizer of her tour, Think Inc, on Thursday wrote to supporters asking them to lobby the Department of Home Affairs to allow Manning into the country.

"We are looking for support from relevant national bodies or individuals, especially politicians who can support Chelsea's entry into Australia," Suzi Jamil, director of Think Inc, wrote.

"We are seeking letters of support to send to the Minister for Immigration in order for him to reconsider his decision."

The department did not comment on the specifics of Manning's case but said that all non-citizens were subject to a judgment of character before being allowed into Australia.

"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 spokesperson said.

Prime Minister Scott Morrison, who previously served as the minister for immigration, said he would discuss the case with Minister for Immigration David Coleman, but said that it was not his "specific responsibility."