Lewis Hamilton said Sunday he found his new Ferrari "really, really hard to drive" in the wet as the seven-time world champion endured a difficult start to his career at the Scuderia.

The 40-year-old is hoping for a new lease of life after his bombshell switch from Mercedes, but it has been a steep learning curve since he joined the Italian team in January.

It culminated in a disappointing 10th in the season-opening Australian Grand Prix, where he was well off the pace of McLaren, Red Bull and Mercedes and behind teammate Charles Leclerc in a rain-hit race, punctuated by safety cars.

"It was very tricky and went a lot worse than I thought it would go. The car was really, really hard to drive today," he said after a race that was marred by a series of crashes in the treacherous conditions.

"For me, I'm just grateful I kept it out of the wall because that's where it wanted to go most of the time."

Hamilton was in the Ferrari not only for his first Grand Prix, but also for the first time in wet conditions.

Clearly still getting used to how his new team works, he was heard on the radio at one time telling his race engineer they had "missed a big opportunity" to capitalize strategically after he led briefly during a series of pit stops under the safety car.

A delayed switch back to intermediate rain tires dropped him back down the field, but the Briton said afterwards there had been "a lot" to take from his debut.

"Just getting acclimatized with the new power unit in the wet conditions," he said.

"The settings it requires are different, and a different way of driving and a different set-up on the steering wheel.

"I hung out as long as I could, got in the lead at one point. Just the guidance with how much more rain was coming, was missing there, so I think we missed out."