Prime Minister John Key was on an Air New Zealand flight that made an unscheduled stop in Tahiti because another passenger became sick.
Air NZ confirms flight NZ28 from Auckland to Houston diverted to Papeete on Saturday night after a customer became unwell.
The customer concerned has remained in Papeete to receive medical attention and the aircraft has since departed.
The flight, operated by a B777-200 aircraft, is now scheduled to arrive in Houston four hours later than originally scheduled.
The airline isn't confirming Mr Key was on board but he tweeted a video previewing a trip to New York for the UN Leaders' Week on Saturday.
"It's going to be a busy trip and there are important issues to tackle," he said.
Fairfax reported Mr Key was on the flight.
Mr Key was scheduled to leave New Zealand on Saturday and returns on September 25.
New Zealand's second term as president of the UN Security Council runs until the end of September.
"I will travel to New York to attend the opening of the 71st General Assembly, deliver New Zealand's statement in the general debate and chair a leader-level meeting of the Security Council aimed at focusing international attention on the conflict in Syria," Mr Key said earlier.
While in New York Mr Key will also hold meetings with world leaders including Helen Clark, and deliver a speech to the Council for Foreign Relations.
While in Houston he's attending events promoting New Zealand business and tourism links.