MELBOURNE -- Sunday's Australian Grand Prix will answer many questions, including how well an 'old' Ferrari can stand up to the new challenge from Williams and McLaren.

Ferrari's decision to leave their apparently revolutionary F2002 at home and bring last year's trusty and record-breaking car to Melbourne could pay off or punish the champions.

Michael Schumacher says the old model, preferred for its reliability in the first race of the season, remains quick enough to beat the rest but he does not sound totally convinced.

"We're going to start the season with the old car which is for sure not what we were aiming for," the four-time champion said when asked about the decision Thursday. "But the old car still represents a fairly good chance of winning the race."

Asked whether it upset him not to be able to use the new car, Schumacher said: "To some degree yes.

"To some degree you are not delighted but what can you do? That's the situation and the situation has obviously been provoked to some degree because we knew we have a backup solution.

"We pushed very hard, everything to the limit, which might pay out later," he said.

"It didn't pay out initially. How much we suffer from that, that's going to be the question that nobody knows."

No decision
Rivals, such as Williams' Colombian driver Juan Pablo Montoya, clearly hope the answer is "lots." But the 'old' car is still not your average second hand model.

It helped Schumacher win nine races last season, including the final Japanese Grand Prix in September and has been improved further since then.

But other teams, particularly Williams with engine partner BMW, have made big strides.

The first three long-haul races of the season, in Australia, Malaysia and Brazil, put a premium on reliability and Ferrari could even wait until Imola in April before introducing the new car.

Schumacher said there was no firm decision yet.

"It depends really how much work we are going to be able to do between now and Malaysia," he said.

"We have one week of testing available, we are going to use this obviously to the maximum and then it depends what kind of job we can achieve."

The problem with the new car is reliability, Ferrari have said as much. Specifics are in short supply while speculation is plentiful.

The car has broken the Fiorano lap record -- as all new Ferraris are supposed to -- but the team have been unable to run it for any great length of time.

The finger of suspicion has pointed to a radical new gearbox but Schumacher preferred to concentrate on a lack of mileage.

"We haven't had enough experience, we haven't done a long run with it because there were a lot of weather issues initially which stopped us and a few mechanical issues which stopped us from running," he said.

"We simply didn't have enough miles on it. We didn't have enough experience to come here with it and be 100 percent certain."

Former Ferrari driver Eddie Irvine, now with Jaguar, said he had spoken to the team's engineers about the problems and had no reason to doubt their explanation.

"They say it's a reliability issue. They think last year's car is fast enough to win it (the race) and it's reliable enough," he said.