The former prime minister scolded colleagues who “insist on having public second thoughts about our own policy”, insisting they hold a minority view within the Coalition ahead of what’s expected to be a heated special partyroom meeting on the issue in Canberra this afternoon.

“Keeping faith with the electorate should weigh just as heavily as deeply-held personal belief,” he writes in The Australian.

“Like it or not, Coalition MPs are honour-bound to oppose same-sex marriage in the absence of a plebiscite that’s supported it.”

Abbott’s sentiments are supported by cabinet ministers Arthur Sinodinos and Mathias Cormann, who insist the government needs to keep its promises and give Australians a say on the issue.

Cormann denied the stoush had anything to do with the prime minister’s leadership, insisting Malcolm Turnbull had the unanimous support of cabinet and strong support within the party room.

Backbencher Dean Smith has drafted his own marriage equality bill and together with Trent Zimmerman, Tim Wilson, Trevor Evans and Warren Entsch, will push for a parliamentary vote on the bill after circulating it to members over the weekend.

There’s also speculation a postal plebiscite proposal will be put to cabinet on Monday and taken to the party room for approval.

Zimmerman says that is possible, but he’s hopeful the rogue MPs can persuade their colleagues.

“I’m always an optimist,” he told ABC radio.

Smith says a postal plebiscite is “useless”, insisting Turnbull is wrong to continue to support a plebiscite.

“The plebiscite is a D-grade response to a defining A-grade social issue,” he told the Nine Network.

Wilson says his electorate of Goldstein has been revealed in numerous polls as having the highest support for marriage equality.

But he pledged to represent the views of those in favour and the 20 per cent who oppose same-sex marriage.

“People who feel strongly against a change in the law, they want their say through a vote and I will communicate that position to the party room because that’s what a good representative should do,” he told ABC TV.

Smith’s bill, expected to be supported by Labor, allows for two people to marry regardless of their gender, while enshrining protections and exemptions for religious communities.

That includes religious ministers, civil celebrants, and businesses linked to a religious body who refuse to cater for same-sex couples.

ReachTEL polling for The Australia Institute and Australian Marriage Equality shows almost two-thirds of voters in Mallee, a Coalition stronghold, support MPs voting according to their own conscience on the issue.

More than two-thirds of voters in Turnbull’s electorate, as well as the electorates of Zimmerman, Wilson, Entsch and Evans, also supported a conscience vote.

Meanwhile, UNSW constitutional law expert George Williams has warned a postal plebiscite would be dangerous and lack legitimacy.

– AAP