Canberra, Jun 1 (IANS): Australian opposition leader Bill Shorten on Monday introduced a same-sex marriage bill in the Federal Parliament.

The Australian Labour Party leader's private members bill proposes replacing the words "man and woman" with the term "two people" to define who can be legally married, ABC reported.

The same-sex marriage debate in Australia gained momentum this week days after Ireland's hugely successful referendum on May 24.

Prime Minister Tony Abbott has emphasised that any moves to legalise gay marriage must be owned by the Parliament, and not just by a single party.

Shorten has called on Abbott to grant his MPs a free vote on the issue.

"When someone has found not just another person they can live with, but a person they can't live without, then they should have the same right to the true qualities of a bond that runs deeper than any law," he said.

"And we say to all young gay people, we are proud of you for who you are..."