A Ferrari test driver will not confirm that the Maranello team is leading the 2019 field.

The paddock consensus is that Ferrari is clearly leading Red Bull-Honda and Mercedes.

Long-serving Ferrari tester and ambassador Marc Gene admits to Diario Sport: "The car debut we had has been very good.

"But we do not know where we are. We know the car is reliable and it responds well to the drivers -- we are very happy with how things are going."

Asked if Ferrari is surprised that Mercedes appears to be struggling in the 2019 pre-season, Gene answered: "I know some people say that, but nobody knows. I promise it.

"We know what fuel we are carrying but we do not know what the others are carrying. We know we're fine, but where we are exactly, we don't know."

Former Ferrari driver Fernando Alonso, who will not be in Melbourne in his new role as McLaren ambassador, agrees with the perception that Ferrari is leading.

"Ferrari looks very strong," he said, "but that was also the case in recent years.

"It's a long season," Alonso added. "The midfield is within three to four tenths, and they seem closer to the top three teams than last year.

"But it's all still reading coffee grounds, because we do not know how much fuel everyone is using."