A Government group is looking at limiting access to common surgical procedures which cost taxpayers $641 million a year.
The National Health Committee has to find savings of $30 million this financial year from elective procedures deemed to be of little benefit.
The money would be used for smarter investment in other parts of the health system.
The only specific elective procedure the committee has so far named for "disinvestment" is the insertion of grommets.
Grommets are tiny ventilation tubes placed in an incision in the eardrum to treat persistent, painful infections called glue ear.
The committee will also evaluate the costs and benefits of new medical technologies. It draws on a Welsh health system report that evaluated 550 elective procedures deemed to be of "relatively low priority".
"Based on New Zealand national data sets," the committee says, "the top 25 procedures on that list in our local context receive public funding of approximately $641 million."
The committee will not name the 25 procedures, saying its work in this area is only preliminary. The Welsh report's specific procedures are listed under 17 surgical and dental headings, including tonsillectomy, grommets, varicose veins, haemorrhoids, dilatation and curettage, hysterectomy, gallbladder removal, caesarean section, lower-back procedures, circumcision, eye-lid surgery, nose surgery and surgery to correct protruding ears.
The committee said it had completed a technological note on the use of ventilation tube grommets for treating middle-ear infections (otitis media).
"The evidence indicates that the use of ventilation tubes is of limited value in treating otitis media with effusion, although it does not suggest that it should be stopped completely."
New Zealand's rate of grommets use is about 75 per cent greater per capita than Britain's.
"The difference represents a cost to New Zealand of approximately $4.4 million per annum," the committee says.
It suggests that by evaluating the whole pathway of care for ear infections - including which children are referred for grommets and where they are treated - "there is potential to both provide children with more appropriate and more effective care, while simultaneously reducing wasted expenditure by DHBs [district health boards]".
Starship children's hospital clinical director of ear, nose and throat services, Dr Muralitharan Mahadevan, said the New Zealand rate for grommets had already fallen. The main indication for the treatment was hearing loss and it had become more common for doctors to apply "watchful waiting".
The committee's chairwoman, children's surgeon Anne Kolbe, said "disinvestment" meant better targeting of procedures, not quitting them altogether.
She said the committee was unlikely to develop its own list.
"All the list does is help us think about where we will look. We will ask the [medical and surgical] colleges where they think we should disinvest."
Kiwis missing out, says heart specialist
New Zealand is missing out on new medical technologies because of a lack of funding and a weak system for evaluating them, an Auckland cardiologist says.
Dr Mark Webster is involved in a trial of a $10,000-per-patient treatment for people whose high blood pressure has not responded adequately to medications.
He said the simple, 20-minute procedure, called renal de-nervation, was extremely cost effective by reducing later strokes, heart failure and kidney failure.
The procedure was being evaluated by the National Health Committee, but Dr Webster said the committee was underpowered and even if it supported the introduction of the procedure, there was no money for it. He said a taxpayer-funded hospital service could introduce the procedure only by cutting something else.
He predicted the committee would fail because of its lack of resources and the lack of funding for new technologies.
But committee chairwoman Anne Kolbe said: "We have decided not to link investment to disinvestment directly." She said the committee had a brief to provide business advice to the Government and the Health Minister on the introduction of new medical technologies.
The committee was establishing links with the Health Research Council and a leading health technology assessment organisation in Canada to set up field trials of new technology.
Health Minister Tony Ryall said: "It is relatively early days with the [committee] and I am confident they will make an important contribution to improving healthcare in New Zealand."