Australia's Finance Minister Penny Wong Tuesday announced her female partner was expecting their first child, sparking renewed debate on the country's ban on gay marriage.

Wong said her long-term partner Sophie Allouache was pregnant, in a statement that also thanked the child's biological father "for giving us the opportunity to raise a child together".

Prime Minister Julia Gillard said she was pleased with the news but remained steadfast in her opposition to gay marriage.

"Penny Wong is a colleague of mine, she's also a very long-term friend, so I'm very pleased for Penny and her partner Sophie as they look forward to a new baby and the next phase of their lives," Gillard told reporters.

"Clearly there are strong views about same-sex marriage in the community. I've made my views clear."

Gay marriage is banned under Australian law and opposed by both major political parties despite polls showing widespread public support for a change to laws to give same-sex couples the right to wed.

Gillard, who is herself unmarried, has repeatedly said that she believes marriage should be between a man and a woman.

Wong said the couple knew the biological father and he would also be known to the child, which is due in December.

"We have chosen to make this statement about Sophie's pregnancy as we understand there may be public interest due to my position," Wong said