Melbourne, Oct 1 (IANS): American anti-abortion activist Troy Newman was detained at Melbourne Airport on Thursday, after travelling to Australia even though his visa had been cancelled.

Newman, who has questioned why doctors who abort babies are not executed, had his visa cancelled by the Australian Immigration Department on Wednesday and was stopped from getting on a flight in Denver, Colorado, ABC reported.

However, he flew on a United Airlines flight, and a spokeswoman for Immigration Minister Peter Dutton said the airline now faces a fine for carriage of a person who does not hold a valid visa.

"Since Newman does not hold a visa, he is unable to enter Australia and remains in the presence of ABF (Australian Border Force) officials at the Melbourne Airport pending his removal," the spokeswoman said.

Lawyers representing Newman said they had withdrawn a Federal Court bid launched on Thursday morning to allow him to enter the country, meaning he will likely be deported.

Newman is the head of anti-abortion organisation "Operation Rescue" and was due to speak at events run by the group Right to Life Australia around Australia.

He said the revocation of his visa was "based on a pile of lies, including the idea that I promote violence".

Operation Rescue said it was shocked by the way Newman had been treated by the Australian government.

"Troy's unjust treatment by the Australian government is based on a pack of bold-faced lies about his character. This makes him a political prisoner," Cheryl Sullenger, a senior policy advisor for Operation Rescue, said in a statement.

Sullenger spent two years in jail for conspiring to damage an abortion clinic in the late 1980s.

Newman is the co-author of the book "Their Blood Cries Out", which was published in 2000.

In the book he questions why doctors who perform abortions are not executed and asks why women or men who request the procedure are not charged with murder.