A law that would allow transgender South Australians to have their gender formally recognised without undergoing surgery will eventually pass, Premier Jay Weatherill says.
A conscience vote on the proposal was lost in state parliament on Thursday with measures to prevent couples being forced to divorce if a partner transitioned also defeated.
The premier has championed the bill but was absent from the evening vote because of a trip to Finland to visit a nuclear waste dump.
Seven other lower house MPs also missed the vote, which was deadlocked on the floor, but lost on the casting vote of the speaker.
Mr Weatherill says the bill will be given another chance either later this year or in early 2017.
"It was a surprise to me to see it presented at a time when there wasn't support for the legislation in terms of the parliament," he told reporters on Friday.
"As I understand it, there is a majority of people that support this bill and it will ultimately become law at some point, either later this year or early next year."
SA Greens upper house MP Tammy Franks said the right faction of the Labor party took the opportunity of the premier's absence to hamper the vote.
"They saw an opportunity and took it, but I doubt the numbers on the floor are a true reflection of the position of the parliament," she said in a statement.
But Mr Weatherill said he had not been undermined by his party as MPs voted based on their personal views.
