Now Red Bull says it will not support Minardi
Horner said Red Bull, which took over from Jaguar in November, could not support Minardi boss Paul Stoddart's request to be allowed to race last year's car with unmodified aerodynamics.
"I sympathise with his position but rules are rules," Horner told Reuters. "They are there for a reason and we all have to abide by them.
"My position and that of Red Bull is that nothing would be more frustrating for us in a debut race to finish ninth with a Minardi ahead of us and a point taken from us."
Stoddart had said earlier that all the teams except champions Ferrari had signed a document agreeing to his request.
However others suggested his list of signatures dated from September and included those of former Jaguar boss Tony Purnell, dismissed by Red Bull in January, and Eddie Jordan who has since sold his struggling team.
Minardi do have their 2005 aerodynamics package in Melbourne but have not tested it, raising potential safety concerns. They plan to introduce their new car next month.
Minardi must either ensure their car complies with the regulations, with front and rear wings changed from last year, or secure a special dispensation from all the other teams before Friday's practice.
Horner's words suggested that would not now happen and undermined Stoddart's claim that only Ferrari boss Jean Todt was standing in his team's way.
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