Finance Minister Penny Wong has announced she and her partner, Sophie Allouache, are expecting a child in December.

In a statement, Senator Wong says the child was conceived through IVF and the biological father is a friend who will be known to the child.

"Like any expecting parents, the prospect of welcoming this child into our lives fills us both with joy," Senator Wong said.

"We are extremely grateful to our IVF service and staff, and to our donor, for giving us the opportunity to raise a child together."

Senator Wong says they have made the announcement about Ms Allouache's pregnancy because there may be public interest, but she asks that the couple's privacy be respected.

Prime Minister Julia Gillard has welcomed the news.

"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, which will be as parents raising a new child," she said.