Australian cricketer Phillip Hughes has died in hospital, two days after the international batsman was struck on the head by a ball during a domestic match.

Governing body Cricket Australia confirmed the 25-year-old had died, casting a dark cloud over the cricket-mad nation, which is co-hosting the World Cup early next year.

Hughes, who played in 26 tests and 25 one-day internationals for Australia, had spent a second night at the hospital in an induced coma after having emergency surgery to relieve pressure on his brain.

He was struck on the head by a ball at the Sydney Cricket Ground when batting for South Australia, a devastating blow that experts compared to the trauma suffered by victims of a car crash.

Australia Prime Minister Tony Abbott described Hughes as "a young man living out his dreams".

"His death is a very sad day for cricket and a heartbreaking day for his family," Mr Abbott said in a statement.

"What happened has touched millions of Australians.

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

The tragic announcement followed calls by former players for the Australian team to abandon the first test of the four-match series against India next week.

Questions about the response time of ambulances dispatched to the stadium have also been raised.

The head of New South Wales Ambulance was to be brought before the state health minister Jillian Skinner today after the ambulance authority issued conflicting statements about their response times.

The arrival of the first ambulance took 15 minutes, NSW Ambulance clarified in a statement yesterday.

The state's median response time for the highest priority "life-threatening cases" was just under eight minutes in 2013-14, according to the authority's statistics.

Dr Peter Larkins, a leading sports physician, told Reuters: "Time is of the essence when your brain has suffered trauma."

News of Hughes's death brought a fresh wave of tributes on social media, with past and present players conveying their shock and grief.

"We are extremely sad to announce that Phillip Hughes has passed away at the age of 25," CA said on its Twitter feed.

"Our thoughts go out to Phillip's family, friends, and the entire cricket community on this incredibly sad day.

"He was not in pain before he passed and was surrounded by his family and close friends.

"As a cricket community, we mourn his loss and extend our deepest sympathies to Phillips family and friends at this incredibly sad time."