February's Bathurst 12 Hour will be without former FIA GT1 World Championship winning team Vita4One.
The German squad had entered two BMW Z4s in what was touted as a major coup for the event.
Owner Michael Bartels has subsequently withdrawn both entries after failing to come up with the budget to fund the trip.
The team had entered Yelmer Buurmann, Jens Klingmann and Niki Mayr-Melnhof in its lead car while looking for funded drivers for the second entry.
The field is now down to 44 cars; six less than what had appeared on the entry list issued by race organisers last week.
Trofeo Motorsports has elected not to campaign its Corvette Z06R, which was to be shared by Jim Manolios, Ivan Capelli and Greg Murphy.
Murphy will instead race at Manfield, New Zealand, on the same weekend in the V8 SuperTourer Series.
The BMW 1M Coupe of Beric Lynton, BMW 135i of Sherrin Racing and John Modystach's Prosurv Racing Mini Cooper S are also late casualties, ensuring the field is nine cars shy of the number that started last year's event.
The top of this year's entry, however, remains heavily stacked with big name international drivers.
The confirmation of Rotek Racing's line-up has added two more stars to the event, with factory Corvette Racing driver Oliver Gavin now set to enjoy his first taste of the Mountain aboard the team's Class B Audi R8.
Gavin is a four-time American Le Mans Series champion and four-time Le Mans 24 Hour class winner with the Corvette outfit, and has previously raced in Australia as part of V8 Supercars' Gold Coast 600.
He will share the Audi with former World Touring Car Champion Rob Huff, British GT Championship driver Richard Meins and American Continental Sports Car Challenge competitor Kevin Gleason.