BEIJING, May 21 (Xinhua) -- Three-time Formula 1 world champion Niki Lauda has died at the age of 70, his family have announced in a statement.

A key figure in the F1 paddock for over four decades, the Austrian had suffered from ill health for the last 12 months, having had a lung transplant last August and then being hospitalised again in January after contracting flu.

Widely regarded as one of the world's fastest drivers at his peak, Lauda was known for his steely determination in bouncing back from a near-fatal crash in 1976, and for setting new standards of professionalism both inside and outside the car.

Lauda began his F1 career with the March team in 1972 before moving to Ferrari, with whom he convincingly won his first championship in 1975.

The Austrian looked set to retain his title in 1976 after winning five of the season's first nine races, but almost lost his life after a fiery crash at the German Grand Prix left him with severe burns and damaged his lungs.

Despite the severity of his accident in an era of F1 where death and serious injury were much more commonplace than today, Lauda's determination to recover saw him back in the cockpit a few weeks later after missing just two races. After a season pockmarked by drama and controversy immortalised in Ron Howard's 2013 film Rush, Lauda was ultimately pipped to the championship by his friend James Hunt.

Undaunted, the Austrian rallied in 1977, sacrificing outright speed for a relentless consistency that saw him take his second drivers' title before leaving Ferrari at the end of the year to join the Brabham team.

Though he took a couple of wins, Lauda became increasingly frustrated at his car's lack of competitiveness, and he abruptly announced his retirement from the sport at the end of the year, claiming he had become bored of driving in circles.

He stayed away for two years, during which time he devoted himself to building up and running his own airline, before being tempted back to F1 in 1982 with the McLaren team, showing he had lost none of his ability by winning the season's third race.

Better was to come in 1984, when Lauda beat teammate Alain Prost by half a point to take his third world championship, completing one of sport's most remarkable comebacks. The Austrian retired for good at the end of 1985, but reappeared in the F1 paddock in the 1990s in a consulting role for Ferrari.

A brief spell in charge of the Jaguar team followed, before he was appointed non-executive chairman of the Mercedes F1 team in 2012, and played a key role within the team until his illness began to prevent him from attending races.

Lauda is survived by his wife Birgit Wetzinger, their children Max and Mia, and his three other sons Mathias, Lukas and Christoph.