Victorian parliament has rubber-stamped Greg Mirabella as the country's newest senator.
But the Liberal must wait until February 8 to take his seat and replace retired former Senate president Scott Ryan.
The Senate, which finished for the year on Thursday, ran out of time to conduct Mr Mirabella's swearing in.
The husband of former Liberal MP Sophie Mirabella has positioned himself as a voice for country Victoria, saying the state's agricultural sector is under-represented in parliament.
He narrowly defeated Treasurer Josh Frydenberg's former adviser Simon Frost to be listed third on the coalition's Senate ticket in Victoria for the federal election, expected in May.
Third spot is widely seen as the ticket's final winnable spot.
Incumbent Liberal senator Sarah Henderson won top spot on the ticket and Nationals' senator and cabinet minister Bridget McKenzie will be listed second as per the coalition's agreement.
