An Austrian privacy group's battle against Facebook goes into the next round in April with the first hearing on a privacy complaint against the social network.

The "Europe v Facebook" group filed a suit last August after using Facebook's own network to sign up 25,000 users for the legal battle.

In total, more than 75,000 users have signed up to the challenge spearheaded by Austrian law graduate Max Schrems.

The campaign group accuses Facebook of spying on users outside the social network, in volation of EU regulations, and of unlawful collaboration with the US government via the Prism surveillance programme exposed by US whistleblower Edward Snowden.

Lawyers for Facebook International, based in Dublin, say the Austrian suit is inadmissible and, on April 9th, will have a chance to present their arguments to this effect before Vienna judges.

But lawyers for Max Schrems and his “Europe V Facebook” complainants have accused the US multinational of time-wasting and say the company’s objections “lack any substance”.

"It seems that they're trying to delay the procedure in part with really bizarre arguments," said Dr Wolfgang Proksch.

The campaigners are demanding that Facebook suspend data collection they say violate EU privacy law and for damages of €500 per claimant -- totaling €10 million for the company.

In court submissions Facebook argued that the users in the class action lawsuit, drawn from over 100 countries worldwide, were not legally capable and cast doubt on whether they had, in fact, transferred their claims to the “Europe V Facebook group”.

The Austria court action came after Mr Schrems dropped his long-running complaint in Ireland that Facebook data collection policies were in breach of EU law.

Mr Schrems abandoned the plan, claiming the Irish data protection commissioner was not prepared to challenge Facebook.