Australian cricketer Phillip Hughes' passed away at the age of 25 after a devastating head injury.

Australian Test cricketer Phillip Hughes passed away in Sydney after suffering a severe head injury. He was 25.

Two days ago, Hughes had been rushed to St Vincent's Hospital after being knocked out by a bouncer during a match between Sheffield Shield and NSW at the SCG on Tuesday.

Australia team doctor Peter Brukner issued a statement saying "It is my sad duty to inform you that a short time ago Phillip Hughes passed away. He never regained consciousness following his injury on Tuesday."

Brukner said Hughes, 25, was not in pain, and was surrounded by his family and close friends.

The 25-year-old collapsed after being struck on the side of the head by a Sean Abbott delivery and was stretchered from the ground. He was undergoing surgery and was in a critical condition.

A statement issued by South Australia Cricket Association had said: "On behalf of the SACA Board and administration, our thoughts and prayers are with Phil Hughes and his family at this time.

"Phil suffered an injury to his head from a delivery Phil has been taken to hospital in Sydney and has been accompanied by family members and SACA General Manager High Performance, Tim Nielsen."

The South Australia Cricket Association CEO, Keith Bradshaw, had spoken briefly to the media, saying he's "very shocked" and "very upset" by the incident.

He had said the outcome of Hughes' surgery is unlikely to be known for 24-48 hours.

Cricket Australia CEO, James Sutherland also spoke to reporters.

"To be honest it sends shudders through you a little bit," he said.

"Pleasingly there was medical attention he was able to receive immediately at the ground.

"All we know is that it's serious and he's fortunate to be in the best possible place right now with experts all around him," he said.

Hughes was given CPR on the stretcher as he came off the field, with Australian opener David Warner alongside him.

At least three ambulances and a helicopter were on hand to treat the 25-year-old and transport him to St Vincent's Hospital.

Australian captain Michael Clarke was one of the first people to rush to the hospital and is currently with Hughes's sister and mother Virginia who were at the SCG.

With agency inputs.