The secretary-general of the Pacific Islands Forum says he believes the whole of the Pacific will mourn the death of the Māori king, Kiingi Tuheitia.
Māoridom is in mourning after the Māori King died peacefully surrounded by his whānau following scheduled heart surgery.
His death comes days after celebrating the 18th anniversary of his coronation.
Baron Waqa said Kiingi Tuheitia was one of the key figures in the Pacific and was well respected in the region.
"I think the whole of the Pacific will mourn his passing," Waqa said.
"We're all here in Tonga, finishing off the leaders' meeting, and this is ... devastating news for us."
Cook Islands Prime Minister Mark Brown said his country would be mourning the Māori king and remembering the great things he had done.
"Haera ra e te ariki," Brown said.
"It's a very sad day for us in the Cook Islands.
"Memories that stick out of the Māori king is a person with such strong belief in his people, his humbleness, his humility that he carried, but also his very strong mana that he carried with him as well," he said.
He said the Kiingitanga had a close connection to the Cook Islands.
Tonga Prime Minister Hu'akavameiliku Sioasi Sovaleni said it was very sad news.
"I'm sure that the people of Tonga feel the loss of this great leader of the Pacific," he said.
"Our thoughts and prayers are with New Zealand."
Hu'akavameiliku said Tonga's King Tupou VI was currently in New Zealand, and the relationship between Aotearoa and Tonga was strengthened by the ties between the two royal families.