Poor pay rates for early childhood educators remain the key reason for the continued exodus from the sector, a royal commission has been told.
United Workers Union executive director of early learning Helen Gibbons said pay wasn't the only issue driving the loss of more than 30 per cent of staff each year, but it remained the most important.
"It's not just about being able to pay their bills, it's also about how they feel valued by the community," Ms Gibbons told South Australia's Royal Commission into Early Childhood Education and Care on Tuesday.
"How much you're paid is a really concrete expression of how much the community values the work that you do.
"I really want to stress that that is the key driver, absolutely the number one issue. Our educators tell us very clearly that if you don't fix that, you don't fix the sector."
Ms Gibbons said other issues raised in a recent survey of staff included the workload on early educators and a lack of support in their roles, both of which led to a sense of frustration.
"They knew what quality early education was and they really wanted to deliver it for Australia's families but really struggled to be able to do so in an environment where they felt isolated, where they felt undervalued, and where their workload was overwhelming," she said.
The royal commission was told the early education sector continued to grapple with an enormous shortage of workers, especially since the COVID-19 pandemic with many leaving the profession, citing burnout and mental health issues, after continuing to work during the global health emergency.
That situation was set to be exacerbated by looming pay increases in the aged care sector which could lure away more staff.
Ms Gibbons said there was no evidence to suggest that workers who had left the early education sector were returning.
"The people that left at the end of COVID, we haven't seen them come back," she said.
"We have for years said we have a leaky bucket. We keep attracting people to the sector but leaders keep leaking out the bottom.
"I think the holes in that leaky bucket have gotten larger and we've lost even more."
The availability of staff will be a key issue for SA after commissioner Julia Gillard recently recommended universal preschool be extended to all three-year-olds through a program to begin in 2026 and be fully implemented by 2032.
Ms Gillard's interim report found that up to 11,130 new preschool places would need to be created at a capital cost of up to $139 million.
Extra ongoing funding to support the system once fully operational was put at between $121m and $357m, with between 1497 and 2180 more staff needed, including teachers, educators and directors.
The commissioner will hand down her final report in August.
