Malcolm Turnbull and Christopher Pyne were the only ministers on the frontbench in the House of Representatives when Liberal backbencher Warren Entsch introduced his private member’s bill to legalise same-sex marriage.

A Senate minister, Simon Birmingham, who has been a strong supporter of same-sex marriage, went into the chamber as an observer.

Tony Abbott, who announced after last week’s special Coalition party room that the issue would be determined by a popular vote, was not in the building. He was visiting an Australian Federal Police training facility to talk about ice.

Turnbull and Pyne have both been outspoken over the last few days, with Turnbull arguing that any popular vote should preferably be before the election.

But Abbott is not intending to give his ministers a say in the timing. He reiterated at a Monday news conference that the vote “will be in the next term”.

This contrasts with Turnbull saying in a blog posted at the weekend that “the government has not made a final decision on the timing of a plebiscite. The prime minister has indicated a disposition to have this considered after the next election. The partyroom has not debated the matter nor indeed has the cabinet.”

Abbott said the government would finalise the precise process for going forward “very shortly”, but indicated that he did not expect it to be when cabinet meets later on Monday.

“We’re not going to dwell on this and we’re not going to drag out the process,” Abbott said.

As Abbott makes it clear he will not bring forward the vote even to the election, the central issue for cabinet is whether it will be a plebiscite or a referendum to change the Constitution. A referendum would very likely go down, because of the stringent requirements for passage.

Abbott has declined to be drawn on this, but his ministers are sharply divided. Social Services Minister Scott Morrison has led the charge for a referendum.

Abbott – who only recently said the question was a matter for parliament – said the decision had to be the people’s choice. “This is something that has been the way it currently is for thousands of years, hundreds of years. It’s a very big decision to make a change like this.” He dismissed the substantial cost of a popular vote.

Entsch went ahead with the cross-party bill despite the Coalition partyroom meeting last week deciding against a conscience vote and Abbott having signalled the bill won’t be facilitated to a vote.

The bill would exempt ministers from marrying same-sex couples if they choose not to do so. But it says it would not be appropriate to extend the right to refuse to perform marriages to civil celebrants.

“Under the Code of Practice for Marriage Celebrants and existing Commonwealth, State and Territory discrimination legislation, authorised celebrants who are not ministers of religion or chaplains cannot unlawfully discriminate on the grounds of race, age or disability.

"To allow other authorised celebrants to discriminate on the grounds of a person’s sex, sexual orientation, gender identity or intersex status would treat one group of people with a characteristic that is protected under discrimination legislation differently from other groups of people with characteristics that are also protected,” the bill’s explanatory memorandum says.

Nor would the providers of services be allowed to refuse them to same-sex couples.

This has recently become one of the issues in the debate, with some arguing that it involves freedom of religion and beliefs.

“It is already unlawful under discrimination legislation for such persons to discriminate on the grounds of a person’s sex, sexual orientation, gender identity or intersex status,” the explanatory memorandum says.

“It is not considered appropriate to provide an exemption on this ground in connection with a marriage, when discrimination on this ground is not allowed generally.

"Persons who provide goods or services, or make facilities available, are currently prohibited from discriminating in connection with marriages on various grounds including race, age and disability. These prohibitions have been in place for significant periods of time.”

Entsch told the House that the bill “is designed to promote an inclusive Australia, not a divided one”.

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