Fernando Alonso thanked the advances in Formula One technology for being able to walk away from a horrific crash at the Australian Grand Prix on Sunday.

About a third of the way through the race, the right front tire on the Spaniard's McLaren collided with the left rear on Esteban Gutierrez's Haas as the Mexican driver braked to make the bend at Turn 3.

Alonso's car was launched at high speed into the trackside concrete barrier and was sent into a barrel roll, flipping twice before coming to rest in a crumpled wreck.

So violent was the force of the crash that fans were left fearing the worst before Alonso crawled out of the cockpit and limped away, shaking hands with a concerned Gutierrez and waving to the crowd.

"I'm thankful for the safety of these cars," Alonso said. "I'm alive thanks to the job of the last 10 to 15 years of Formula One."

Alonso would have been forgiven for closing his eyes at the impact, but was alert throughout and his thoughts immediately went to family back home.

"I was flying, so you see the sky then the ground, then the sky, then the ground," Alonso said.

"You want to stop but it doesn't stop. It keeps going and going and going. It was quite scary, but at the last moment the car stopped and I had a little space to go out and I said 'I will go out quickly because my mother will be watching at home.'"

Gutierrez quickly made his way over to the stricken McLaren and gave Alonso a handshake and embrace, clearly thankful that no greater harm was done.

"It was a big relief to see that he was fine," Gutierrez said. "It was a very scary moment and not very pleasant to see how his car ended up.

"We were both a bit shocked from the crash. We came together and spoke a little bit, but we're all good most importantly."