Two experienced government senators have effectively been dumped by the Queensland Liberal National Party for the next federal election.
Former Howard government minister Ian Macdonald was relegated to the fourth position on the LNP ticket in a preselection battle on Friday.
The position is considered unwinnable.
The top spot went to Brisbane mining executive Paul Scarr, with businesswoman Susan McDonald in second place and finance executive Gerard Rennick in third position.
Another sitting senator, Barry O'Sullivan, narrowly missed out on preselection, having gone for the second spot on the ticket.
The fifth and sixth positions went to Brad Carswell and Nicole Tobin, respectively.
Based on historical trends, Queensland voters will almost certainly elect two LNP senators at the next half-Senate poll due by May 2019 but a third is unlikely.
Senator O'Sullivan entered the upper house in 2014, filling the seat vacated by Barnaby Joyce.
The former police officer and grazier has chaired a number of committees and served as Nationals whip in the Senate.
Senator Macdonald is the longest continuously serving senator in the upper house, entering the chamber in 1990.
He served in the Howard government as minister for regional services, forestry, fisheries and conservation.
The 73-year-old north Queenslander has repeatedly declined to step aside despite pressure from LNP colleagues.