Every second, a toddler's brain forges more than a million new neural connections - making early education critical for development.

But on the world stage, Australia still sits near the bottom of the class. Just 15 per cent of three year olds attend preschool compared with an OECD average of 68.6 per cent.

Right now, four year olds can access 15 free hours of preschool a week - or up to 600 hours a year.

While the federal government has made no pledge to expand the program nationally, the ACT, along with Victoria, Tasmania and NSW, is pushing ahead with plans to roll out the subsidy to three year olds.

In the territory, where childcare prices are among the highest in the country, the expansion will be staggered over the next four years to ensure centres can cope with demand, Education Minister Yvette Berry says.

A number of children from disadvantaged backgrounds had already been identified for the free hours as well as more targeted wrap-around family support, Ms Berry said, but the next years of the roll-out were still being ironed out.

"[For kids] starting two years behind it's very hard to catch up," she said.

Early Childhood Australia boss Samantha Page said Australian families were increasingly being priced out of kindergrten, leading to large gaps in the vocabularies of disadvantaged kids arriving at school.

"If we can provide two years of high quality education to children, we can make a real difference," she said.

"We see it in NAPLAN results, we see it in PISA, we see it in lifelong ... wellbeing and earnings. [It's] not about teaching the letters of the alphabet, preschool is about teaching children how to get along, to [self-regulate], to undertake inquiry."

In the past, children often learnt those early skills playing in the street with the neighourhood kids or as part of a larger family brood.

"Now preschool is where it happens," Ms Page said.

Some kids starting behind did catch up before school and many disadvantaged families still prepared their children wonderfully for the big step through the school gates, Ms Page said.

"I don't want it to sound like it's inevitable," she said. "But the statistics tell us that there are risks."

Research pointed to 15 hours a week as the minimum required to improve outcomes, and she said vulnerable children would benefit from additional hours long term.

But Ms Page acknowledged the logistics of expanding universal access to three year olds were not for the fainthearted, backing the ACT's "measured" roll-out.

"There are considerable issues around workforce shortages and access to services," she said.

Under the ACT model, particular attention will be paid to improving early intervention and support for children in need, including those experiencing trauma and family violence, as well as training up staff to respond to its signs.

Ms Page said catching difficult behaviours early could save years of problems down the line.

"It's connected to the issues we're having with violence in schools," she said.

Ms Berry said early childhood educators would receive the first family violence training, but primary and high schools would benefit down the line as part of a broader package being rolled out across the ACT public service.

"Around 22,000 workers will be trained in identifying people ... who may be victims or perpetrators of family violence," Ms Berry said.

"That's a significant number of people who will now be having a conversation about [violence] who may have not ever had it in the past...that's when we start to see a real change in violence in our community and put an end to it."

The capital's existing Koori preschools, which offer culturally appropriate education for Aboriginal and Torres Strait Islander children, will also expand along with the early intervention service Prep for Pre, which has been piloted since 2017.

"[We've had] really positive feedback from families around Prep for Pre," Ms Berry said.

"What we did was bring in services like speech therapists and physiotherapists to help young people and their families understand what were their extra needs were and ... prepare for kinder."

Four new pilot programs for after-hours preschool care will also kick off with grants of $50,000 each.

Ms Berry said the government's complete early childhood strategy would be released in the coming months.

Four-year-old preschool access is currently funded two thirds by the states and a third by the Commonwealth.