Facebook owner Meta announced on Wednesday it would challenge in court an EU demand for fees under a content moderation law.

The European Commission last year put Meta's Facebook and Instagram on a list of "very large" online platforms that face tougher rules under the new Digital Services Act (DSA).

Companies on the list must pay fees to the commission, the EU's executive arm, to bankroll enforcement of the DSA.

Meta supported the DSA's aims and had introduced measures to comply, "but we disagree with the methodology used to calculate these fees," a company spokesperson said.

"Currently, companies that record a loss don't have to pay, even if they have a large user base or represent a greater regulatory burden, which means some companies pay nothing, leaving others to pay a disproportionate amount of the total," the spokesperson said in a statement.

The landmark DSA law demands the platforms do more to clamp down on illegal and harmful content, including the dissemination of disinformation. It also requires them to do more to protect online consumers from fraud.

It is part of the EU's bolstered legal weaponry to rein in Big Tech, alongside another law that seeks to curb the dominance of the world's biggest tech firms.

The commission deems platforms that have at least 45 million active monthly users in the European Union -- equivalent to 10 percent of the bloc's total population -- to be "very large".

The DSA law came into force last year for bigger companies but all firms must be compliant by February 17 this year.

The commission refused to comment directly on Meta but a spokesperson said: "It is the right of companies to appeal. Our decision and methodology are solid. We will defend our position in court."

The fees had been due on December 31, 2023 and the commission spokesperson confirmed all of the companies paid.

The fee is calculated "in proportion to the size of the service" and does not exceed "an overall ceiling (set at 0.05 percent of the annual worldwide net income) for each provider," the spokesperson added.

Meta is not the only one taking its grievances with the DSA to court.

Online retailers Amazon and Zalando are also on the EU list but are challenging their designations.