THOUSANDS of parents across NSW will have to pick up their children from childcare early today as workers stage a walkout in protest at low wages.

At least 30 centres will be involved in the action in Sydney, with centres closing at lunchtime to attend a major rally at Martin Place at 4pm in the biggest industrial walk out to date over the long-running issue.

Despite losing a test case at the Fair Work Commission – where they argued they should be paid as much as men in the manufacturing sector – childcare workers are continuing industrial action.

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Today’s walk-off is the fourth in 18 months, with 7000 workers across Australia leaving work early and 350 centres closing at lunchtime or early afternoon to send delegates to the rallies.

According to the union, United Voice, 40,000 parents will be hit by the action.

Union boss Helen Gibbons said the salary of workers – as low as $22 an hour for tertiary trained educators – was unfair.

“Parents have been informed if their centre will be walking off,” she said. “Educators are walking off the job with the unwavering support of parents who have chosen to keep their children at home for the afternoon so that their educators can participate.”

The industrial action was raised at the NSW budget estimates hearing, with Early Childhood Minister Sarah Mitchell asked if she supported the higher pay claim.

“When it comes to issues of pay parity yes … I’m aware of those matters … but ultimately the rates are pay are set by the Fair Work Commission at a federal level,” Ms Mitchell said.

“I’m aware of the intention of industrial action tomorrow but ultimate a matter for the Federal Government and the Fair Work Commission.”

Questions were also raised over how many pre-schoolers would benefit in NSW from a new government scheme to fund community preschool for three year olds.

The State Government has announced $200 million in subsidies for all three-year-olds to attend preschool from next year, but childcare experts have questioned the value of the program, saying at least 83 per cent of children that age will miss out.

Quizzed on what proportion of three-year-olds will take up the offer, Early Childhood Minster Sarah Mitchell took the question on notice.

Opposition early childhood spokeswoman Kate Washington said the ALP estimated the scheme would help just five per cent of three-year-olds in the state.

“When more than 80 per cent of the State’s three year olds obtain their preschooling in long daycare services, and community preschools are full of four year olds, the government’s “universal” three year old funding is a lie,” she said.

Following this year’s budget, nine large early learning providers signed an open letter to Premier Gladys Berejiklian saying the scheme was far from ‘universal’.

The Australian Childcare Alliance said “the vast majority of NSW-based three year-old children will fail to see any benefits from the… proposal.”