The 'three-day guarantee', first announced by Prime Minister Anthony Albanese in December 2024, will replace the previous government's activity test that gave subsidies to families earning up to $530,000.
The change means 100,000 more families are eligible for the additional days of care, which kicked in on January 1.
Early Childhood Education Minister Jess Walsh said families will no longer be locked out of subsidised care under the universal system.
"Every child deserves access to quality early learning – no matter their postcode, or what their parents do for work," she said in a statement.
"Too many children have been locked out of quality early education and care because of their parents' work or study activity."
A report by the Productivity Commission in September 2024 recommended the activity test be scrapped because it was hurting families who needed it most without leading to "substantial" increases in workforce participation.
The activity test required each parent to work, study or look for work for at least 16 hours each fortnight in order to access 72 hours of subsidised care, the amount now assured through the three-day guarantee.
The Albanese government is investing $430 million across four years to deliver the policy.
Treasurer Jim Chalmers said it would provide working families "with more choice immediately".
"Whether it's cheaper childcare, cheaper medicines, or increased payments for students and carers, we are delivering more help for those who need it most from the start of 2026," he said.