Three patients who have been clinically dead for at least 40 minutes have been brought to life by doctors in Australia using a new resuscitation technique.

Colin Fiedler, 39, had suffered a cardiac arrest and 'died' for 40-60 minutes last June, before being brought back to life  at Melbourne's The Alfred hospital, according to The Herald Sun.

"I'm so grateful, more than I could ever say," he told the paper.

The technique used by doctors was using a mechanical CPR machine called the Autopulse, which performs continuous chest compressions, and a heart-lung machine to transmit blood and oxygen through the patients' body.

The new techniques were used on seven patients, and three of them have been successfully brought back to life after being clinically dead for 40-60 minutes.

Although the Autopulse CPR combined with the heart-lung machine techniques are still in testing period, The Alfred hospital hopes that the method can be used in other hospitals.

The Autopulse CPR is not new – it has been in existence for many years. However, the combination of Autopulse CPR with the heart-lung machines is a novelty.

See below for a video on resuscitation through Autopulse CPR.