The First Tier Tribunal was expected to conclude this month but will now take place on 16-18 January.
It is understood the Scottish champions do not expect to learn their fate until the end of the season, with a final decision potentially coming months after the conclusion of the tribunal.
If Rangers lose the case, they could face a tax bill of £49million and the possibility of the club being plunged into administration.
The Govan side are also involved in a separate dispute with HMRC over a £2.8million tax bill, which first emerged in April. They are believed to be disputing a fine that goes with it.
Owner Craig Whyte - who completed his takeover in May – admitted last month his club are facing a “crisis situation” over the larger tax case.
He said then: “What we have to remember is that Rangers are in a crisis situation. It’s a hard thing to live with. I think we need to get finality on it.
“We need to move forward and, even though it may be a tough process, we must try to remove the uncertainty that is hanging over us. The club is paralysed right now.”