Health Minister Tony Ryall is under fire for choosing not to take up his seat at the heart of the World Health Organisation in Switzerland.
New Zealand's three-year term on the WHO's powerful, 34-member executive board ends this year.
The board meets at least twice a year to recommend policies
to the World Health Assembly, the annual meeting of all WHO member states, and to implement the assembly's decisions.
At its next six-day meeting in Geneva, starting on January 18, the board will discuss topics including the International Health Regulations, prevention of non-communicable diseases and strategies to reduce alcohol abuse.
Emeritus Professor Robert Beaglehole, of Auckland University and a former director of the WHO's department of chronic diseases and health promotion, said it was unfortunate Mr Ryall would not attend the board meeting.
A deputy director-general from the Health Ministry will replace him.
"This is a missed opportunity for New Zealand to play a key leadership role in global health matters as we have in the past. It's a rare opportunity because we won't get elected to the executive board for another 15 years or so."
Professor Beaglehole, who retired from the WHO in 2007, said the board set the agenda for assembly meetings. "It's a very influential group."
He said the Labour Government had sent its health ministers to WHO meetings.
Mr Ryall said last night he had decided not to attend the board meeting himself because money was tight "and I don't think my attendance at this meeting is a priority".
"We have a senior official from the ministry attending and I'm happy with that. If I went to every international conference I would never be in the country. My priorities are here in New Zealand, working to improve front-line health services: more elective surgery, faster emergency departments and quick cancer treatments."
He said he had not been overseas as Minister of Health. He had intended to go to the assembly meeting last May but withdrew after swine flu hit New Zealand.
