National is being accused of cronyism after three people closely affiliated with the party were appointed to the board of a new agency for promoting health programmes.
The seven-person board of the Health Promotion Agency, announced on Friday, includes former National MP Katherine Rich and two National Party campaign leaders.
Prime Minister John Key has already defended the appointment of Mrs Rich - who is chief of the Food and Grocery Council - when it was pointed out that she was head of an influential lobby group.
The council has lobbied on behalf of the food and beverage industry against proposals to reduce salt and sugar in food, and against the mandatory inclusion of folic acid in bread.
Mr Key said it was important that the board had a range of views.
Alcohol watchdogs have previously criticised Mrs Rich's placement on the agency's establishment board, saying she was the most outspoken defender of the alcohol industry and its right to sell booze cheaply and at all hours.
The agency, which would produce promotions on nutrition, injury and disease prevention, was chaired by Dr Lee Mathias, a former nurse and deputy chair of the Auckland District Health Board. Dr Mathias was also electoral chair for National MP Sam Lotu-Iiga.
Another board member, insurance broker Jamie Simpson, was electoral chair for Cabinet Minister Gerry Brownlee.
Labour Party State Services spokesman Chris Hipkins said political involvement should be a barrier to Government appointments, especially in advocacy areas.
"I think the Government needs to tread very carefully. Three National Party office-holders on one board, particularly given the nature of the board, with an advocacy role, it seems to me is pretty questionable."
He was concerned that the presence of three National members would heavily influence the agenda of the new organisation, which would create programmes on key areas such as alcohol use and obesity.
The Health Promotion Agency combined the Alcohol Advisory Council of New Zealand (ALAC), the Health Sponsorship Council and some of the Ministry of Health's promotion work.
Its board also included former squash player and Health Sponsorship Council member Dame Susan Devoy, ALAC chair Rea Wikaira, AUT University professor of public health Grant Schofield, and University of Auckland lecturer and nurse Barbara Docherty.
National Addiction Centre director Doug Sellman said: "There is no conflict of interest if you ignore the relationship between health and the commercialisation of addictive products such as alcohol and recreational food."