Red Bull advisor Helmut Marko says close friend Niki Lauda is unlikely to return to the Formula 1 paddock at the Australian GP in March.

The Austrian triple world champion had set the season opener in Melbourne as his target to once again be back in the Mercedes garage following emergency lung transplant last summer after falling ill.

However, last month would see a setback to his recovery as a flu virus saw Lauda back in a Vienna hospital in intensive care as a precaution before being released.

"Lauda still has a long way to go, he needs a lot of patience", Marko told German broadcaster RTL. "Lauda will support his team by telephone."

Niki's son Mathias offered more insight into his father's battle and his bid to once again overcome the odds.

"Dad has undergone a complex operation and has had bad moments, but he has a strong character and is fighting," he told La Gazzetta dello Sport.

"He needs to do physiotherapy to recover his energies. He trains with fury and I hope that soon we will see him in shape.

"I speak to him every day. When I'm not there, with him there is my brother Lucas. One of us is still in Vienna."