Mark Shand, the Duchess of Cornwall's brother, has died after he sustained a serious head injury during a fall, BBC News reported.

The 62-year-old was in New York when the incident happened on Tuesday night.

In a statement, Clarence House said it was with "deep sadness" that it had to confirm Shand's death.

"The duchess, the Prince of Wales and all her family members are utterly devastated by this sudden and tragic loss," Clarence House said.

Described as a man of "extraordinary vitality, a tireless campaigner and conservationist," Shand was the duchess's only brother.

As the chairman of the Elephant Family, a movement which exists to save the endangered Asian elephant, he did incredible work and focused on the project up until his death, according to BBC News,

The news of the death comes as the Duchess of Cornwall and the Prince of Wales prepare for a high-profile tour of Canada next month.

"Shand, the duchess's only brother, reportedly slipped while lighting a cigarette and hit his head on the pavement outside an after-party for a charity event," BBC News reported.

"According to the New York Police Department, the emergency services picked him up where he fell outside the Rose Bar and took him to Bellevue Hospital, where he was pronounced dead on Wednesday."

The conservationist and travel writer had been in New York for a charity auction at Sotheby's, which was in aid of unprivileged children and the Elephant Family, BBC News reported.

"Shocked & saddened to learn of the death of one of my closest English friends, Mark Shand, in New York where he was raising funds 4 charity," Imran Khan, former Pakistan international cricketer and politician, tweeted.

Band Aid co-founder and former Ultravox frontman Midge Ure also tweeted, "Dreadful news about Mark Shand. I worked with him on his Elephant charity in Edinburgh. A true gentleman."

Shand was married to French actress Clio Goldsmith. They have a daughter called Ayesha, aged 19.