The European Commission (EU) has opened a formal investigation into the parent company of social media sites Facebook and Instagram over concerns that the platforms may "stimulate behavioral addiction" in children.

The Commission said in a statement that systems of both Facebook and Instagram, including the algorithms, may exploit the weaknesses and inexperience of minors and cause addictive behaviour.

It also noted concerns over so-called "rabbit-hole" effect which it said draw you in to more and more disturbing content.

The European Commissioner for Internal Market, THIERRY BRETON said the bloc was not convinced Facebook and Instagram had done enough to comply with the bloc's Digital Services Act.

The company could face fines of up to 6 per cent of its global revenue if it is found to have broken the rules.