The New Zealand High Commissioner to the Cook Islands, Brian Donnelly, says he's disappointed that ill health has forced him to resign.
Mr Donnelly, who has been associated with the people of the Cook Islands since the 1970's, took up the three-year posting in February.
However, this week he handed in his resignation to the Foreign Minister, Winston Peters.
Mr Donnelly says the job was perfect for him, given his history with the people of the Cook Islands
"It's a dream job for me, it was working really for the people of the Cook Islands whom I love, but also looking after the interest of New Zealand, and you can't get anything better than that."
Mr Donnelly will return to Auckland for medical treatment.