Education Department officials said while data is only available for the first three months after the changes started in July 2018, the early signs are encouraging.

About 2.5 per cent more children were attending childcare at the end of September than the end of June, a Senate committee heard on Thursday.

There had also been a 24 per cent boost in the number of indigenous kids in formal childcare, up to 42,000 compared with the previous year.

And more than four in five families were able to get subsidies for either 76 or 100 hours a fortnight (four or five days of care) because of the amount of work, study, volunteering or job searching parents were able to do.

"That's a much stronger result than we assumed in our modelling," department deputy secretary Jackie Wilson told the estimates hearing in Canberra.

"So, more families and children accessing childcare, higher levels of activity being accessed."

Almost 94 per cent of families receiving the subsidy had taxpayers cover between 50 and 85 per cent of their fees.

Wilson said other measures of the new system's success, particularly in relation to community centres which were previously funded in a different way, would take more time to see.

Under the new system, parents can access a single subsidy for their child care fees but must meet means and activity tests.

AAP