A tribunal has ordered Sosefo Lakalaka to leave New Zealand by 16 May.
Mr Lakalaka said he and his family were very sad that his appeal to stay in New Zealand was rejected.
The 53-year-old received a kidney transplant in New Zealand a decade ago but it's now failing and he wants to stay because Tonga can't provide the treatment he needs.
In November last year New Zealand's Immigration and Protection Tribunal denied Mr Lakalaka's appeal against deportation.
