PARENTS failing to ensure their children undergo the full six-stage immunisation risk losing up to $2100 as part of an expanded scheme that replaces a small carrot with a big stick to increase vaccination rates.

From next July, the government is axing the $258 ''maternity immunisation allowance'' paid irrespective of income to families of fully immunised children aged up to five. Instead the government will require parents have their children fully immunised or forgo three payments of $726 available under the family tax benefit A end of year supplement.

About nine in 10 children are immunised and not being immunised "is a real risk" ... Health Minister Nicola Roxon. Credit:Alex Ellinghausen

The family tax benefit A goes to about 90 per cent of families with young children and the payment provisions will apply for the financial years when the child is one, two and five years of age.

The Health Minister, Nicola Roxon, and the Families Minister, Jenny Macklin, yesterday said the scheme provided ''stronger immunisation incentives'', but also delivered savings of $209 million over four years. About nine in 10 children are immunised now and not being immunised ''is a real risk'' to the child's health and that of others, Ms Roxon said.