Official papers reveal the Treasury is not convinced about the worth of increases in the tax on tobacco and cigarettes.
Advice released under the Official Information Act shows that Treasury believes excise rises for tobacco control are not highly effective and that other policies should be explored.
In April, the excise on a packet of cigarettes rose 10% and that on loose tobacco 24%. There are two more 10% increases over the next 18 months.
The Ministry of Health estimates that that will reduce the incidence of smoking by 6.5% in the next decade.
Despite the Treasury's view, Associate Health Minister Tariana Turia maintains that excise rises work; in fact, she says, she wanted to go further and have even bigger rises.
Ms Turia says other possible changes include banning retail displays of tobacco products and selling them in plain packaging.