Hundreds of childcare centres across Australia are closed today as workers walk off the job to protest against low wages.

The protest is the first since their union, United Voice, lost a five-year battle at the Fair Work Commission for a wage increase.

Comparing the pay of childcare workers to others The national minimum wage is currently $18.29 per hour

The national minimum wage is currently $18.29 per hour The average full-time Australian wage is currently $42.84 per hour

The average full-time Australian wage is currently $42.84 per hour Childcare workers with a certificate III are paid an hourly award rate of $21.29

Childcare workers with a certificate III are paid an hourly award rate of $21.29 A metal fitter, who also has a certificate III and trains for the same period of time, makes an average of $39.47 per hour

The workers want the Federal Government to subsidise a 30 per cent pay rise for the nation's 108,000 childcare workers.

The union says that about 320 centres have been closed by the action, and about 30,000 families are affected.

"This has enormous support," the union's assistant national secretary Helen Gibbons said.

"From Darwin to Tasmania, from the east coast to the west coast, we are going to see early educators walking out of their centres and joining various rallies and actions across the country, and they'll be joined by parent groups and the wider community," she said.

"We know the Government massively underinvests in this sector. If we are going to achieve professional pay for early educators, either parent fees go up or the government funding needs to improve, and no-one wants to see parent fees go up.

"The Government needs to step in and take seriously their responsibility to fund this sector properly."

Staff at Monash Caulfield Child Care Centre are among those taking strike action. ( ABC News: Joanna Crothers )

In a statement, federal Education and Training Minister Simon Birmingham said he expected "all early learning and childcare centres to value their employees and pay them as much as they can afford".

"Many already do pay above the award," he said.

Senator Birmingham insisted "the role of Government is not to run those centres but to help families access affordable care".

Today's action is the third rally agitating for a change in the past 12 months.