The Turnbull government is committed to a plebiscite on same-sex marriage, but won't use the method to resolve other social issues, such as euthanasia.
Attorney-General George Brandis said the legalisation of same-sex marriage was a "unique issue".
"I don't see that method of resolving a complex or difficult social question being adopted in relation to other difficult or trying social questions," he told Sky News on Sunday.
Senator Brandis was asked several times whether the government intended to take the same-sex marriage plebiscite, that was rejected by the parliament, to the next election.
"That policy has not changed," he told Sky News.
The plebiscite was rejected by the parliament earlier this year, with Labor, the Greens and others wanting a conscience vote for MPs.
Senator Brandis also declined to say whether he thought a planned private member's bill from West Australian Liberal senator Dean Smith to force a parliamentary conscience vote would pass the Senate where the government does not have a majority.