On advice from doctors Alonso will have to wait for his competitive return with McLaren until the second race in Malaysia later this month.

Although given a clean bill of health after sustaining concussion in a heavy crash in the second pre-season test in Barcelona on February 22, the fear of ’second-impact syndrome’ has forced Alonso’s hand.

The term refers to a second concussion occurring when the effects of the first are still subsiding, potentially resulting in severe brain injuries, or even death.

Although the timespan between the accident and Alonso returning to the car for first practice in Melbourne on March 13 would appear to be sufficient, he is not prepared to take any risks.

Via his Twitter account, Alonso said: “It will be tough not to be in Australia, but I understand the recommendations."

It will be tough not to be in Australia, but I understand the recommendations. A second impact in less than 21 days "NO"#countdownMalaysia

— Fernando Alonso (@alo_oficial) March 3, 2015

For the Albert Park event Alonso’s seat will now be occupied by Kevin Magnussen, demoted to reserve driver following the Spaniard’s arrival after a full season with the team in 2014.

A thrilled Magnussen, who will partner Jenson Button in Melbourne, tweeted: “Shame about the circumstances but still I’m so excited to be racing in Melbourne. Can’t wait!!”

Shame about the circumstances but still I'm so excited to be racing in Melbourne. Can't wait!! #BelieveInMcLarenHonda

— Kevin Magnussen (@KevinMagnussen) March 3, 2015

To which a sporting Alonso replied: “best of luck at the race mate!”

Explaining the circumstances behind the decision taken to withdraw Alonso from Australia, McLaren have revealed doctors found the 33-year-old to be “asymptomatic”, with “no evidence whatsoever of any injury” and “entirely healthy from neurological and cardiac perspectives”.

But given the prospect of second-impact syndrome Alonso was “advised he should not compete in the imminent Australian Grand Prix meeting”.

A McLaren statement added: “Fernando has understood and accepted that advice.

“Fernando’s doctors acknowledge he feels fit and well, and he regards himself as ready to race.

“That being the case they are comfortable with the fact he has already recommenced physical training, with a view to preparing for a return to the cockpit of his McLaren-Honda car for the Malaysian Grand Prix meeting on March 27, 28 and 29.

“Indeed, his doctors are supportive of that ambition, satisfied as they are that he sustained no damage whatsoever during his testing accident on February 22.

“All at McLaren-Honda fully support Fernando’s decision in respect of his doctors’ advice.”

Double world champion Alonso has returned to McLaren for this season after spending the past five years with Ferrari, burying the hatchet with Group CEO Ron Dennis following an ignominious campaign with the team in 2007.