Conservative Liberal Zed Seselja has defended his absence from a historic vote on same-sex marriage, despite pledging to back the national survey result in Parliament.
The Assistant Minister abstained in Wednesday's Senate vote on a bill put forward by Liberal Dean Smith, joining Liberal frontbenchers Michaelia Cash and James McGrath, and Nationals senator Bridget McKenzie, outside the chamber.
Senator Seselja said before the 2016 federal election he would likely abstain in any vote after the government's proposed plebiscite, but has since repeatedly pledged to respect and honour the national result.
In August he told a constituent he would vote to support the bill if a national yes vote was returned.
"If the people vote yes, I will vote yes," he said on Facebook.
In interviews during the postal survey campaign, Senator Seselja said he would "respect" and "honour" a 'yes' result and called on other MPs to do the same.
"I'd call on everyone to honour the will of the Australian people as expressed through this plebiscite, so for those of us who are arguing against change, if it goes against us, we should honour it. That's what I'll do," he told Sky News in August.
Asked about the inconsistencies on Wednesday, Senator Seselja said he abstained because he could not support the Smith bill.
"Prior to the 2016 election I said that I didn't support same sex marriage but in the event of a yes vote I would not frustrate the will of the Australian people but would likely abstain," he said.
"I fought hard to include reasonable protections in the bill but they were all rejected. I could not vote for a bill that would compromise freedom of speech, freedom of religion and parental rights.
"I nevertheless honoured my promise to not frustrate the will of the people and abstained as indicated just a few days before the election."
Neither of the ACT's senators were present for the vote.
Labor frontbencher Katy Gallagher said she would have voted in support of the Smith bill but was at Sydney's Westmead Children's Hospital on Wednesday as one of her children underwent major surgery.
Senator Gallagher was present as the Senate considered amendments on Tuesday night.