More than 10,000 high-end child car seats are being taken off store shelves across the country over serious safety concerns.

About 6,000 units of Maxi-Cosi's Euro Convertible Car Seat A2 model are to be officially recalled from sale this Friday over safety concerns.

It comes after 5,000 units of a later model, the A4, were removed from sale last Friday.

The A2 model is to be recalled after parents found the straps of the model could dangerously loosen while driving.

The A4 model was voluntarily removed by the company last week after it emerged the model was distributed without having its safety standard certification, meaning it was effectively being sold illegally.

Motoring groups across the country have warned consumers about the danger of the products.

The Royal Automobile Association of South Australia (RAA) issued the initial warning.

RAA spokeswoman Belinda Maloney said the safety flaw in the A2 model could allow a child to be ejected from the seat.

She was also concerned about the A4 model.

"It's an illegal restraint — shouldn't be sold, shouldn't be used," she said.

"Obviously for retailers that's a problem for them."

The makers of the seats, Dorel, said under the recall of the A2 model the company would provide a replacement cover, which made it safe to use.

Owners of the A4 model would be offered a replacement.

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More than 250,000 Maxi-Cosi seats sold in Australia per year

Maxi-Cosi is sold in more than 80 countries, and sells more than a quarter of a million car seats each year in Australia.

Dorel spokeswoman Sharyn Perry said the company had not been able to replicate the fault on the A2 model online without purposely misusing the product.

She said the product was phased out in March but some retailers could still have some for sale.

"Consistent with our priority of continuous improvement in safety and through internal testing, we have been able to further improve the fitting by increasing the space around the trim and the harness adjuster," she said.

She said the A4 model's sale without certification was "an administrative oversight".

"Importantly, all dynamic testing is complete and we have documentation our A4 car seat passed crash lab testing," she said.

"There can be a lag between passing dynamic testing, documentation sign-off and receiving the official certification certificate."

Royal Automobile Club of Victoria road user manager Melinda Spiteri said they were disappointed an uncertified child restraint model was on sale in Australia.

"Our members and all parents of young children should be able to have confidence in products available for purchase," she said.

ACCC to investigate if company mislead consumers

The Wong family thought $600 would buy them a top-quality child car seat. They were wrong.

They first discovered there were issues when a car seat fitter discovered the Maxi-Cosi A2 seat's straps would loosen and posted the vision online.

The family checked their car seat and discovered the same issue.

Eujinn Wong said he wanted the best for daughter Madison. ( ABC TV )

Eujinn Wong, father of four-week-old Madison Wong, said he was distressed to think what could have happened.

"We want the best for her, particularly when it comes to safety," he said.

"The entire time she's been riding in what essentially is an unsafe seat."

Consumer watchdog Australian Competition and Consumer Commission (ACCC) said it would investigate concerns with the Dorel models.

"The ACCC is in contact with Dorel to ensure that an effective recall is put into place quickly," a spokesman said.

"Dorel Australia has advised consumers that the [A2] restraint is still safe to use until a replacement cover has been received, as long as the owner checks that the harness adjuster is always clear from obstruction before driving anywhere."

The watchdog will also consider whether the company engaged in misleading practices.

"The general rule is that if you make claims that your goods meet specific standards, those claims must be true," it said.

Concerns about the seats were first raised on social media, when a car seat fitter posted a video highlighting the problem in the A2 model.

Discussions continued for about two weeks, but it was not until official media inquiries this week that the company announced they would formally recall the A2 model.

It understood motoring authorities were aware of issues during that time.

The video has had more than 200,000 views and more than 2,300 shares.