Sauber's application and appeal hearing against the Supreme Court of Victoria's ruling that Giedo van der Garde drive in Australia will take place on Thursday.
A Swiss arbitration court last week ordered the Hinwil squad hand the Dutch driver one of the race seats for the season-opener in Melbourne on the basis of a contract he signed with the team, but Sauber decided to fight the matter.
However, Supreme Court Justice Clyde Croft on Wednesday upheld the Swiss decision, stating "I am not satisfied that there are grounds to refuse enforcement".
He added: "The submission of this matter to arbitration was clearly made on the assumption of all parties that the relevant agreements between the parties were entered into in order (among other things) to facilitate van der Garde’s involvement as a driver for the Respondent."
The judge further added that the ruling applies "to the whole of the 2015 Formula 1 season – not just in relation to the coming few days in Melbourne for the Australian Grand Prix".
Sauber have already appointed Marcus Ericsson and Felipe Nasr as their drivers for the 2015 season and CEO and team principal Monisha Kaltenborn have confirmed they will appeal the decision.
"We are disappointed with this decision and now need to take time to understand what it means and the impact it will have on the start of our season," she said.
"What we cannot do is jeopardise the safety of our team, or any other driver on the track, by having an unprepared driver in a car that has now been tailored to two other assigned drivers."
The Supreme Court of Victoria has announced that the appeal will take place at 09:30am local time on Thursday.
Meanwhile, Sauber have until Thursday 4pm local time to inform the FIA which two drivers will race for them in this weekend's Australian GP.