Since August, the federal government has issued notices to more than 60 centres which have either broken the law or put children at risk.
Thirty of those are required to show they've fixed the issue by the end of February.
The government says it is working with nine centres - the majority of which are day-care providers - which have failed to resolve the issues raised.
The operators could be blocked from receiving the government's childcare subsidy as a consequence.
Friday also marks the start of mandatory child-safety training for staff in the early learning sector, and a national register of workers.
More than 100,000 employees across Australia have already registered for the training, the government said.
The $45 million national register aims to better track childcare staff as they travel across states and territories.
It will also keep records of employees' qualifications, working-with-children checks and other identifying information.
The reforms follow a series of allegations about children being abused in early learning centres.
In one of the most egregious alleged cases, Melbourne man Joshua Dale Brown has been hit with more than 150 charges, accused of abusing 12 children.
His case remains before the courts.
The reforms taking effect on Friday would better protect children, Education Minister Jason Clare said.
"We are doing this all for a reason. There is nothing more important than our kids and keeping them safe," he said in a statement.
27°C