Thai authorities were preparing Sunday to conduct an autopsy on the body of Australian cricket superstar Shane Warne, who died of a suspected heart attack, before flying him home where he will receive a state funeral.

Police said there was no foul play suspected in the 52-year-old's death after he was found unresponsive in a luxury villa on Thai holiday island Koh Samui late Friday.

The "King" of spin's unexpected passing sparked a global outpouring of grief from prime ministers, rock stars and fellow players, an acknowledgement that the Melbourne native transcended his sport.

On Sunday, Warne's three children reacted to his death, with friend and manager James Erskine saying they were "in complete shock".

"Jackson [Warne's eldest son] just said 'We expect him to walk in the door. This is like a bad dream'," Erskine told Australia's Channel Nine.

The player -- one of the greatest Test cricketers of all time -- was found unresponsive in a Samujana resort villa on Friday after failing to meet friends.

Warne was taken to the Thai International Hospital Samui at about 6:00 pm (1100 GMT), but his management said despite medical efforts "he could not be revived".

Officers on the holiday island said Saturday "no foul play was suspected" following an initial investigation and confirmed Warne's body would be transported to Surat Thani for an autopsy.

Early Sunday AFP reporters saw a body placed in an ambulance from the morgue where Warne's body had been kept overnight.

Relatives had "already coordinated with the Australian Embassy so that right after the autopsy's finished, they will take his body back to Australia," said local police chief Yutthana Sirisombat.

Speaking outside Koh Samui's police station Andrew Neophitou, a close friend of Warne, said: "We really just want to get Shane home, that's all it is."

- 'Greatest characters' -
Prime Minister Scott Morrison led tributes to one of the country's "greatest characters" on Saturday and announced Warne would receive a full state funeral.

Over the weekend fans gathered at the Melbourne Cricket Ground to lay flowers and some unusual offerings -- among them cigarettes, beer and meat pies -- to remember the famously hard-charging athlete.

Credited with reviving the art of leg-spin, Warne was part of a dominant Australian Test team in the 1990s and 2000s and helped his country win the 1999 limited-overs World Cup.

His tally of 708 Test wickets has been surpassed only by fellow spinner Muttiah Muralitharan.

Bursting onto the scene as a brash young player with a shock of blond hair, Warne became almost as well known for his colourful life away from cricket as he was for his exploits on the field.

The first bowler to take 700 Test wickets with an assortment of leg-breaks, googlies, flippers and his own "zooters", Warne retired from Australia duty in 2007 following a 5-0 series win at home to arch-rivals England.

Warne played 145 Tests in total over a 15-year career, taking 708 wickets, and was also a useful lower-order batsman, with a highest Test score of 99.

He was a "hero" to the current generation of cricketers, said Australian captain Pat Cummins.

"The loss that we are all trying to wrap our heads around is huge," he said.

- 'Beloved Lionheart' -
Following his international retirement, Warne continued to star on the Twenty20 franchise circuit, appearing for Rajasthan Royals in the Indian Premier League and his hometown Melbourne Stars in Australia's Big Bash League.

He later became a highly regarded television commentator and pundit, renowned for his forthright opinions, and was involved with coaching, working individually with current-day leg-spinners.

Warne was divorced from wife Simone Callahan, with whom he had three children.

His former fiancee, actress Elizabeth Hurley, said on Instagram the "sun has gone behind a cloud forever", adding: "RIP my beloved Lionheart."

Cricketers mourned his passing, with India batting great Sachin Tendulkar tweeting of his ex-rival: "Shocked, stunned & miserable... Will miss you Warnie. There was never a dull moment with you around."

Pakistan leader and ex-player Imran Khan paid his respects to "a bowling genius", while former Australia teammate Adam Gilchrist said he was "numb".

Tributes came in beyond the sporting world from Rolling Stones frontman Mick Jagger, singer Ed Sheeran, to actors Russell Crowe and Hugh Jackman.