United Voice ACT alleged the Little Learning School in Forde has been hiring trainee staff to replace more-experienced employees and neglecting to provide entitlements or sufficient training to juniors.

But a spokeswoman for the childcare centre said the union's numerous allegations were incorrect and all employees were paid according to Fair Work requirements, with some paid well above the award rate.

"We have provided the union significant amount of information and evidence about this approximately six months ago and never heard back from them," she said.

It is understood the union has engaged lawyers to launch proceedings in the Federal Circuit Court.

The union alleges management at the centre have been forcing staff to pay for their own training sessions and had not provided them with time to complete their training at work.

"This course of conduct has led United Voice to suspect that Little Learning uses trainees as a cheap form of labour rather than as students in early education," said a spokesman.

Little Learning School management said trainees paid for their enrolment fees but were not forced to pay for the traineeship.

"Employees have been provided the time legally required and when there is 'spare time' available, this has been further provided," said the spokeswoman.

The union has alleged the northside centre is trying to operate at the lowest cost possible, is avoiding legal obligations, and has not taken training seriously.

"Between January and September 2014, the trainees were provided with virtually no training time," said a spokesman.

But the school has dismissed this allegation and said the trainees were part of a government-approved and accredited training academy that is managing all the training.

"The trainees are in direct contact with the training academy and we obtain updates about their progress," she the spokeswoman.

"There is obviously also a significant amount of other training the centre is providing to employees on an ongoing basis."

According to the union, a group of trainees was fired by the union in 2013, with one sacked without notice in front of three or four parents.

"Yesterday, Little Learning terminated the employment of four workers including three members of United Voice," said the spokesman.

"This happened at the same time as Little Learning hired a tranche of new trainees to replace the old ones."

But the childcare centre once again rejected the union's allegation and stressed it "did not terminate or fire anyone".

"However, we did have staff that had completed their traineeship with us that were not offered further employment," she said.

"This is the norm in the industry and in some cases, a centre will offer them employment after the traineeship depending on their performance and positions available at the centre."

The union has also claimed trainees are being used to perform duties that usually attract higher rates of pay, such as working in the kitchen.

A formal statement of claims is expected to be lodged by the union next week.