Federal cabinet has reaffirmed support for a national vote to decide on same-sex marriage.
The comment by minister Christopher Pyne on Friday came as a Liberal senator said he would press ahead with a bill to change marriage laws, arguing the plebiscite was "divisive" and aimed at delaying change.
West Australian Dean Smith will be among Liberal MPs attending a special partyroom meeting in Canberra on Monday, convened to discuss a way forward on the issue.
Mr Pyne said the "overwhelming view" of the partyroom was to support the current policy.
"The first step is a national vote to bring the Australian public with us - that is the policy that has been reaffirmed by Malcolm Turnbull, by the cabinet and by me here today," Mr Pyne told Sky News.
Nationals leader Barnaby Joyce, who discussed the issue with federal colleagues in Rockhampton on Friday, told reporters he wouldn't be offering advice to Mr Turnbull on how to handle the issue.
"One thing they can't stand is to get instruction or commentary from the National party, just like the National party can't stand commentary from the Liberal party about us," Mr Joyce said.
The Nationals have been firm in support of the plebiscite since it was first flagged in 2015.
Senator Smith said allowing Liberal MPs a free vote in parliament was in line with the tradition of Robert Menzies and John Howard.
It also delivered on a key party principle - equality before the law for all people.
"The time is now for a parliamentary vote on same-sex marriage," he told Sky News.
The public had lost confidence in the idea of a plebiscite, he said, describing it as a "tool for delay."
Liberal colleagues have flagged the idea of a postal vote, which would not require parliament to pass a bill and would be cheaper.
Senator Smith, who plans to circulate his bill over the next week, said a postal vote could be challenged in the courts.
He dismissed claims it was a test of Mr Turnbull's leadership.
Mr Turnbull on Thursday said he was standing by the plebiscite, as promised at the 2016 election, and any change of policy was a matter for the joint coalition party room.
One Nation leader Pauline Hanson has urged Mr Turnbull to stand firm.
"Show leadership and be strong about this," she told Nine Network.
Independent senator Lucy Gichuhi said all Australians needed to have a say about what was a "fundamental change to such an ancient institution like marriage."
Crossbencher Derryn Hinch and the Nick Xenophon Team continue to oppose a plebiscite.
Labor leader Bill Shorten says his party would support a move to suspend business in parliament to bring on a private member's bill.
He does expect a "very small number" of Labor MPs will still vote against same-sex marriage.