Puna, who is the chancellor of the Suva-based regional university, will be a special guest at the event.
He was in Fiji last week to attend the Pacific meeting of the Ocean Summit which will be held in June.
Health minister Nandi Glassie will also be out of the country, attending a meeting in Malaysia. He left the country yesterday for the Asia Pacific Ministerial Forum of Management of Social Transformation.
The five-day meeting will end on Thursday and Glassie is due to return home on Sunday.
Deputy prime minister Teariki Heather will also be out of the country in Auckland on a personal visit.
The remaining ministers are expected to remain in Rarotonga this week.