Prime Minister John Key says the death of former Cook Islands prime minister Sir Geoffrey Henry is a sad day for the island nation.
Sir Geoffrey, who led the country for a decade from 1989 after a brief stint as caretaker prime minister in 1983, was 71 when he died on Wednesday night.
He had been sent home from hospital on Saturday where he had been receiving treatment for cancer.
Mr Key said he believed he met Sir Geoffrey once.
"Obviously we were saddened to learn of his death. We respect the role he played as former prime minister of the Cook Islands."
The government's sympathy was extended to the people of the Cook Islands and there would be appropriate representation at his funeral.
Arrangements for a state funeral were under way.
Labour's Pacific Island Affairs spokesman Su'a William Sio said Sir Geoffrey was a "shining star of Cook Islands politics".
Sir Geoffrey, who quit politics in 2006, was named speaker of the Cook Islands parliament in February last year.
He became a Knight Commander of the British Empire in 1992.
A New Zealand-trained lawyer, in 2010 a terrorism-related comment to a flight attendant led to him being asked to leave an Air New Zealand flight at Auckland.