Danna Vale, a lawmaker from the ruling centre-right Liberal Party, said on Monday she worried that immigrants from Muslim countries could eventually outnumber native-born Australians if the current rate of abortions continued.
Her comments came as members of the House of Representatives prepared to debate whether to strip regulatory control of an abortion drug, mifepristone - also known as RU-486 - away from Tony Abbott, the health minister, and hand it to the country's main drug regulator, the Therapeutic Goods Administration.
The TGA has control over all other drugs in Australia, but a 1996 law shifted regulatory authority over RU-486 to the health minister. Last week, the Senate voted 45-28 to hand control of the drug back to the TGA, a move expected to pave the way for the drug to be cleared for use in Australia.
Explaining her opposition to the bill, Vale said: "A certain imam ... actually said that Australia's going to be a Muslim nation in 50 years' time."
"I didn't believe him at the time, but when you actually look at the birth rates and when you look at the fact that we are aborting ourselves almost out of existence by 100,000 abortions every year ... that's five million potential Australians we won't have here (in the next 50 years)," Vale said.
"When you actually look at the birth rates ... we are aborting ourselves almost out of existence by 100,000 abortions every year"
An outspoken supporter of the bill and fellow Liberal Party member, Amanda Vanstone, Australia's immigration minister, said Vale's suggestion that people from Muslim countries might eventually outnumber native-born Australians was "completely ill-founded".
Vanstone said: "That's just a complete misunderstanding of how our migration programme works and where our source countries are. I just don't know where this idea has come from. It's just not possible."
She said most immigrants come to Australia from England, New Zealand, China, India, South Africa and the Philippines.
One of the bill's co-sponsors, Lyn Allison - who last week told the Senate of her own personal experience with having an abortion - slammed Vale's remarks as "outrageous".
Allison said: "They're very unfortunate from almost every point of view. I think the prime minister should come out and say that was ill-considered and that she ought to apologise."
Members of the opposition Labour Party have also called on Vale to retract her comments, labelling them bizarre.
Kevin Rudd, the Labor Party's spokesman for foreign affairs, on Tuesday said: "Everyone's entitled to their point of view but that's seriously a weird one."