The king, 72, was hospitalised in a KwaZulu-Natal hospital for diabetes treatment, local media reported.

"Tragically, while still in hospital, His Majesty's health took a turn for the worse and he subsequently passed away in the early hours of this morning," read the statement, issued by Inkatha Freedom Party founder and traditional prime minister to the Zulu monarch Prince Mangosutho Buthelezi, on behalf of the royal family.

"On behalf of the Royal Family, we thank the nation for your continued prayers and support in this most difficult time."

In 2019, the king and Queen Pumi joined the Prince of Wales and the Duchess of Cornwall to mark the 140th anniversary of the Anglo-Zulu War.

The couples at the 100th annual Royal Welsh Show in Llanelwedd, where they watched a military display by a Zulu impi regiment in traditional leopard-skin uniform.

In a statement, South Africa’s President Cyril Ramaphosa said he was deeply saddened by the news of the king’s death.

“His Majesty will be remembered as a much-loved, visionary monarch who made an important contribution to cultural identity, national unity and economic development in KwaZulu-Natal and through this, to the development of our country as a whole,” he said.