Its not a small number of day-cares, only the minority would allow unvaccinated children.
Its compulsory to report and publish vaccination levels at schools. Vast majority of parents don't want their kids at schools with unvaccinated peers, and its that parental pressure that drives it more than any Government policies
..However
Unvaccinated children banned from childcare across NSW as conscientious objector loophole closed
From January 2018 children who are not fully immunised to their parents' conscientious objection to vaccines will no longer be able to be enrolled in child care.
Its called the No Jab No Play law hehe, google : no jab no play nsw 2018