Minardi's chances of starting Sunday's Australian Grand Prix remain in doubt after Red Bull denied supporting their struggling rivals.
Minardi's participation in Melbourne is in doubt
Minardi have not been able to afford to comply with new rules aimed at slowing Formula One cars down.
They can race if all the other teams give their approval and claimed only Ferrari had refused their consent.
But Red Bull team boss Christian Horner said: "I sympathise with their position but rules are rules."
He added: "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."
Minardi team owner Paul Stoddard had claimed that Ferrari were the only team withholding support.
He said: "I hope that this can all be sorted away from the track. Hopefully by Friday morning I can proudly say there are 10 signatures."
Stoddard has spoken to Ferrari boss Jean Todt about the issue but failed to make any progress and said he would make a fresh bid later.
"On Thursday night when Todt gets in I'm going to go to his hotel," the Australian said.
"Without that signature we're in trouble. They are keeping me out but let's hope that is over."
The row is wrapped up in the ongoing political dispute over the future of F1, in which Ferrari are on one side and the nine other teams on the other.
It concerns the distribution of F1's commercial rights revenues and the governance of the sport's rules by Max Mosley, president of governing body the FIA.
As part of it, several of the teams - including Minardi - believe that the new rules were imposed illegally.
Stoddart added: "Todt kept saying it's an FIA problem although Max Mosley has gone on the record and said if we got Ferrari's signature then we can race.
"I tried to explain that to him rationally.
Stoddart (right) in discussion with F1 boss Bernie Ecclestone
"I asked him to delegate the powers to some other member of Ferrari who was actually in Melbourne so we could at least have the discussion.
"He refused, and the phone call came to an end without a conclusion."
If the row is not resolved, Minardi's cars are likely to be declared illegal when they are presented for scrutineering by race officials on Thursday in Australia.
Stoddart would then be faced with the choice of making hurried last-minute changes to the cars - or taking his battle to a higher authority.
"As a last resort, and I mean last resort, there is always the option of the High Court to challenge the legality of the regulations," he said.
"But on this, the 10th anniversary of the Melbourne Grand Prix, I would not want to be the one to spoil the party."
Minardi have been saying for months they want to use an updated version of their 2004 model car for the first three races of the season in Australia, Malaysia and Bahrain.
They then plan to switch to their 2005 cars for the first European race in San Marino, Italy.
Ferrari and Jordan are also starting off the season with last year's cars but have made changes in accordance with the FIA regulations, which include extended engine mileage, limited tyre changes and restricted aerodynamics.
Stoddart said last month that he was confident he would win any court battle over F1's rules.