Carlos Sainz expressed confidence Thursday he was fit enough to drive his Ferrari in Melbourne but will decide whether to race after seeing how his body holds up in practice.

The Spaniard underwent surgery for appendicitis two weeks ago, forcing him to miss the last grand prix in Saudi Arabia, where teenage reserve driver Oliver Bearman came seventh.

Sainz said he was improving by the day, having spent the last fortnight in recovery rather than training.

"Every day I'm feeling a lot better, the first week was tough. That was when you see things a bit darker," he said ahead of Sunday's Australian Grand Prix.

"But in the second week the recovery sped up a lot and I started to feel confident I can jump in the car tomorrow and do well.

"I'll see how I feel, I'm feeling positive about it."

Sainz came third behind winner Max Verstappen and the Dutchman's Red Bull teammate Sergio Perez at the opening race of the season in Bahrain.

Red Bull repeated the one-two feat in Jeddah, where Sainz's teammate Charles Leclerc filled the podium.

While Sainz has been given the all-clear from doctors and is keen to race, it is not clear how his body will react to the demands of Formula One.

"I'll let you know tomorrow when I get back in the car and the G-forces throw me around a bit," he said, referring to first practice in Melbourne on Friday.

"But I feel ready. I've done as much as possible to recover and you cannot imagine the effort and logistics that I have done to be fit for this race.

"I'm very happy with the progress I've made and now, as I said, it's time to jump in the car and see how I feel."

Sainz is leaving Ferrari at the end of the season to make way for Mercedes' seven-time world champion Lewis Hamilton.