Thousands of kids are missing out on early education because of their postcode, with the childcare crunch pushing parents away from the workforce.
One in four Australians have severely limited access to childcare and about 700,000 people have virtually no access at all, Victoria University researchers found.
The findings underscored Australia's incredibly patchy access to child care, Georgie Dent from community group The Parenthood said.
"We know quality early childhood education and care is absolutely fundamental to supporting the education and development of children," Ms Dent told AAP.
"If you've got whole populations not being able to access early education and care, you are setting up a whole generation of children to miss out."
For many families relying on two incomes to keep afloat, pulling out of the workforce to care for kids had a huge impact on their budgets.
"A lot of families who live in regional, remote, rural areas, they can only dream of it being too expensive because they don't even have the option of choosing that," Ms Dent said.
The Victoria University study mapped childcare access across nine nations for more than 10 million children, tracking approaches that provided fairer access for families.
"For the first time, we can see the impact of different government policies and how nations compare," lead author and institute director Peter Hurley said.
Across Australia, France, England and Wales, affluent areas had better access to childcare.
"These are the neighbourhoods that also have higher childcare fees, showing providers are attracted to areas where they can charge more," the study found.
Sweden and Norway bucked this trend, offering fair access regardless of wealth.
Of the nine nations tracked in the study, Australia ranked fourth for childcare access.
About 24 per cent of Australians live in a childcare desert, where there are more than three children per childcare spot.
The figure was down from 35 per cent in 2020 data.
Researchers attributed the improvement to an increase in childcare spots, steady birth rates and slightly different calculations.
Achieving universal childcare would require substantial changes to the system, Professor Hurley said.
"We normally leave it up to the market to decide where to operate and sometimes that works really well," he said.
"What this research shows is sometimes it doesn't."
More funding in areas with thinner childcare markets could help address shortfalls, Prof Hurley said.
The federal government had shown positive ambitions to achieve universal childcare but existing models favoured services in the most profitable areas, Ms Dent said.
"We wouldn't accept the argument that if you happen to live in an area that doesn't have a primary school, then your children will miss out," she said.
Early Education Minister Anne Aly sought to pin blame on the former coalition government.
"We inherited an early learning system that isn't responding to the needs of regional and rural families," Dr Aly said.
Government subsidies had made early learning affordable for more than one million families, she said.
One in four were from the bush.
The government has agreed to fund a 15 per cent pay rise for childcare workers and allocated funding to keep open services in disadvantaged communities.
The Productivity Commission has handed the Albanese government a report on child care, which has not yet been released.
