The high court has declared the postal survey on same-sex marriage will go ahead.
Two groups of same-sex marriage advocates attempted to stop the postal survey, arguing the government should not have bypassed parliament in funding it.
The government found the $122 million by using laws to make an advance payment to the finance minister in circumstances where there is an urgent need for spending and the situation was unforeseen.
The full bench of the High Court handed down their decision in Melbourne at 2.15pm on Thursday, during Question Time in federal parliament.
The challengers argued the spending was neither urgent nor unforeseen, two key requirements for advancing money from the pool of funds that can be used without parliamentary approval.
The survey forms are due to be mailed from Tuesday, September 12.