The broader cricket community has gathered on-field at the SCG tonight as they mourn the death of Phillip Hughes.

Immediately after the news of Hughes’ passing broke, mourners began to gather on the ground where the devastating injury occurred.

Michael Clarke was among those paying respects, having earlier read a statement on behalf of the Hughes family.

A distraught Clarke spent a long period out in the middle on his own as other players made their way out onto the centre wicket area one-by-one.

Flags at the SCG are at half-mast tonight, as are those at Lord’s, traditionally known as the home of cricket.

Hughes died in hospital two days after he was hit by a bouncer during play at the SCG.

A close friend of Hughes, Clarke delivered the family’s statement at St Vincent’s Hospital earlier today.

"We are devastated by the loss of our much-loved son and brother, Phillip," Clarke said.

"It's been a very difficult few days and we appreciate the support we have received from family, friends, players, Cricket Australia and the general public.

"Cricket was Phillip's life, and we as a family shared that love of the game.

Phillip Hughes has died following Tuesday's incident at the SCG.

"We would like to thank all the medical and nursing staff at St Vincent's Hospital and Cricket NSW medical staff for their great efforts with Phillip - we love you."

Cricket Australia team doctor Peter Brukner confirmed that the star batsman never regained consciousness following Tuesday's tragic accident.

"Phillip and his family have been surrounded by hundreds of people, all of whom have come to wish him well," he said.

"I'd like to pay tribute to the St Vincent's hospital team who have done a magnificent job."

Dr Brukner said he was "impressed at the care Michael (Clarke)" gave to the Hughes family.

"Phillip's always been like a little brother to the Hughes family," he said.

Flags at the SCG are flying at half-mast following news of his death. (9NEWS)

In an press conference at the hospital, Dr Brukner said a key blood vessel had been damaged when a short ball struck Hughes in the neck while batting.

"Phillip took the blow at the side of the neck and as a result of that blow, his vertebral artery – one of the main arteries to the brain – was compressed by the ball," he said.

Former cricketing great Michael Slater arrives at the SCG to join other past and present players supporting each other in the wake of Phillip Hughes' accident. (9NEWS) ((9NEWS))

"That caused the artery to split and for bleeding to go up into the brain.

"This is frequently fatal at the time. However, Phillip was resuscitated by Dr John Orchard, the Cricket NSW doctor, and paramedical staff."

Tributes have started flowing for the young cricketer who has been described as a "positive, generous spirit" and who was once hailed as the next Sir Donald Bradman.

All flags across NSW will be lowered to half mast tomorrow, as requested by Premier Mike Baird.

In Hughes' childhood town of Macksville, mourners were urged to come to the Macksville Ex-Services club and "share some time together".

Prime Minister Tony Abbott released a statement following Hughes' death and described him as a "young man living out his dreams".

"His death is a very sad day for cricket and a heartbreaking day for his family," the statement read.

"What happened has touched millions of Australians.

"For a young life to be cut short playing our national game seems a shocking aberration.

Brad Haddin and Aaron Finch at St Vincent's Hospital. (AAP)

"He was loved, admired and respected by his teammates and by legions of cricket fans."

South Australian Cricket Association (SACA) chief executive Keith Bradshaw said the entire cricketing world is "in shock" following the tragic death.

"He had many friends and team-mates both here and interstate that will need support and is it important we offer them our love and care as we all come to terms with this tragic event," he said.

"He was a much-loved and a truly remarkable talent, and I think we are very lucky to have experienced having him in our playing group for the past two years."

Cricketer Aaron Finch and Australian coach Darren Lehmann leave St Vincent's Hospital after visiting Phillip Hughes. (AAP)

Hughes' injuries sent shock waves through the cricketing world, with messages of support pouring in from current and former Australian cricketers as well as players from around the world.

An emotional Joe Hockey described the loss as "desperately sad".

"For Phillip I offer my prayers. For Phillip's family I offer my deepest condolences. For Sean Abbott, I join with the nation in offering unqualified support during this desperately difficult time," the federal treasurer said.

Ricky Ponting, Peter Siddle and James Pattinson have flown in from Melbourne today while Aaron Finch, Matthew Wade and Peter Forrest touched down yesterday.

Cricket Australia yesterday called off the entire round of Sheffield Shield matches out of respect for Hughes. Some have called for the First Test to be cancelled.

Particular concern is being held for Sean Abbott, the NSW paceman who delivered the ball which felled Hughes.

Opposition Leader Bill Shorten said the game was enriched by Hughes' passion.