The designs of the diffusers on the Brawn, Toyota and Williams have led to questions from rival teams, who think the trio are unfairly using a bigger diffuser than was originally intended by the regulations.
So far the FIA has said that it believes the designs are within the wording the regulations, but the matter has moved up a gear with at least one team believed to have written to the governing body to state its belief that the design is illegal.
Now, FIA president Max Mosley has said that he thinks the matter can only be sorted out in Australia - because it is too late to organise a formal hearing before the first race.
In an interview with The Daily Telegraph on Saturday, Mosley said: "It's a very clever device and you can make a very good case for saying that it's legal and a very good case for saying that it's illegal. It's going to be difficult.
"What's actually happened is that teams are saying 'We think it's illegal for this and this reason.'
"If there had been more time before the detailed objections to the system were sent in, I would probably have sent it to the FIA Court of Appeal before Australia. And actually I have given thought to that this week. But there isn't time. It wouldn't be fair. I think the thing will probably come to some sort of a head in Australia."
The most likely outcome from the current situation is that one or more teams may choose to lodge a protest at the first race of the season - either once scrutineering has taken place on Thursday or after the finish of the race.
Mosley added: "One possibility is that all the teams agree that it is illegal, and therefore all the teams shouldn't have it from Barcelona. But then those teams who say it is legal will say 'Why should we do that?' And those that say it's illegal will say 'Why should we lose an advantage for four races?'
"And so probably what will happen is it will end up going to the stewards, who will make a decision. That will almost certainly be appealed by whichever side is disadvantaged. And then that will go to our Court of Appeal and be hammered out.
"It's not straightforward. I have an open mind on it at the moment - I can see it going either way. I really can. But somebody has to make their mind up and fortunately it's not my job."