A spokesman said Mr Pohiva had been resting in hospital in Nuku'alofa since last week.
He had extensive medical care for a liver condition in New Zealand earlier this year, and after returning home in June was under instructions to rest but the spokesman said he started working too early and got tired.
But he said Mr Pohiva is intending to go to India this week for a meeting, and to Tuvalu next week for the summit.
Meanwhile Kaniva News reports the Noble MP Lord Fusitu'a has been airlifted to Auckland for medical treatment.