Facebook can be ordered to police and remove illegal content worldwide, Europe's top court has said, in a landmark ruling that rights activists say raises concerns some countries could use it to silence critics.

The judgement means social platforms can be forced to seek out hateful content deemed illegal by a national court in the 28-country bloc rather than wait for requests to remove posts as it currently does under EU rules.

Facebook and other platforms can also be made to comply with requests to take down content globally, even in countries where it is not illegal, the Luxembourg-based Court of Justice of the European Union ruled.

"EU law does not preclude a host provider like Facebook from being ordered to remove identical and, in certain circumstances, equivalent comments previously declared to be illegal," the court said in a statement.

"In addition, EU law does not preclude such an injunction from producing effects worldwide, within the framework of the relevant international law."

The judgement came just a week after the same court told Google that it does not have to apply Europe's "right to be forgotten" law globally, garnering praise from freedom of speech advocates as courts try and figure out just how much responsibility for content platforms should take.

In the Google case the court decided that the right to have personal data deleted was not absolute and freedom of information needed to be considered too.

The ruling against Facebook is limited to court orders and doesn't apply to wider complaints by users alleging that certain content is illegal.

Facebook slammed the decision, saying that it was not the role of social platforms to monitor, interpret and remove speech that may be illegal in any particular country.

"It undermines the long-standing principle that one country does not have the right to impose its laws on speech on another country. It also opens the door to obligations being imposed on internet companies to proactively monitor content and then interpret if it is 'equivalent' to content that has been found to be illegal," the company said.