Parliament's health committee is considering whether parents should be offered cash incentives to have their children immunised, or even have benefits withheld if they don't without good reason.

Committee members were in Canberra last week looking at several issues including how Australia had dramatically improved its childhood immunisation rates and will report to Parliament on its trip.

Chairman and National MP Paul Hutchison said 91 per cent of Australian 2-year-olds were now fully immunised against little more than 50 per cent 10 years ago. In New Zealand the rate is about 75 to 80 per cent.

Australia's success had been been achieved with a seven point plan, including some measures such as a childhood immunisation register which is already in place here.

However, Dr Hutchison said he was particularly impressed with the effectiveness of cash incentives for families and health professionals in increasing immunisation rates.

Parents of 18-month-olds who had received all required shots received a A$125 ($163) cash payment. Another payment was made to parents of fully immunised 4-year-olds.

Other measures included requirements at some schools and pre-schools for children to be fully immunised before they could be enrolled.

Children not immunised could be enrolled when parents had demonstrated a "clear issue of conscientious objection" to their doctor, Dr Hutchison said.

But parents who didn't get their children immunised and couldn't satisfy medical authorities they had legitimate objections could have some childcare benefit payments withheld.

Australia also has cash incentives for health providers such as GPs both for achieving high rates of immunisation amongst their patients and for providing data to the immunisation register.

"I can't pre-empt the committee report's recommendations but I personally think that they've got some very good ideas and the incentives are quite innovative and they say have worked very well," Dr Hutchison said.

"There is no doubt in my mind that we should do a similar sort of thing using instruments that are appropriate to New Zealand. This is one of the most clear-cut effective evidence base ways to help children and in fact help the whole population."

Immunisation Advisory Centre research director Helen Petousis-Harris saw some value in cash incentives for parents but believed "but being very careful that its about making a decision, not about forcing people to do something they're not happy about".

Last year's UNICEF State of the World's Children report rated New Zealand 33rd out of 35 developed countries for rates of childhood immunisation.