Parents are now required to provide evidence of their child's vaccination, or an approved exemption, after consultation with their immunisation provider, at the time of enrolling their children in childcare.

While similar requirements have always been in place, Kiama MP Gareth Ward said the difference was that operators now faced fines of up to $4000 if inspectors found children in their care who did not have proof of vaccination.

"Previously, early childhood education and care services have only been required to request that parents and guardians provide an Immunisation History Statement and keep a register of that information," Mr Ward said.

"However, children could still be enrolled if the information was not provided. This loophole has now been closed and children won't be enrolled unless the required documentation is provided."

Mr Ward said changes made to the Public Health Act 2010 had massively strengthened vaccination requirements for children enrolling in childcare in NSW.

Under the changes, early childhood education and care services cannot enrol a child unless the parent or guardian has provided documentation that shows the child is fully vaccinated for their age, or has a medical reason not to be vaccinated, has a parent or guardian who has a conscientious objection to vaccination or is a child on a recognised catch-up schedule.

He said at least 95 per cent coverage was needed for effective disease control, according to health experts.