Fernando Alonso insists he will be back very soon

Two-time Formula One world champion Fernando Alonso has said he expects to be back racing "very soon" despite spending three nights in hospital after suffering concussion in a crash last weekend.

Alonso crashed into a wall after completing just 20 laps on the final day of the second pre-season test on Sunday and was airlifted to hospital under sedation.

He was released from hospital on Wednesday, but was sent home to the northern Spanish city of Oviedo to rest and recuperate by his McLaren team rather than take part in the final testing session in Barcelona this week.

"As you can see I am completely fine. I would like to be at the test this week in Barcelona, but the doctors recommendations say I have to wait a little bit," Alonso said in a video posted on his official Twitter account.

"I will rest this weekend and I will give you an update next week with the progress and see you very soon on the track."

McLaren chief executive officer Ron Dennis said on Thursday that he "can`t forsee any reason" why Alonso wouldn`t be fit to drive in the first Grand Prix of the season in Melbourne on March 15.