Some 200 Finns protested Thursday against a proposed law supported by Nokia and other companies that would give employers the right to monitor workers' emails if wrongdoing is suspected.

"Down with Big Brother. Lex Nokia, full of mistakes," the demonstrators -- mostly young adults -- chanted outside parliament where the law will be voted on later this month.

"Lex Nokia is very problematic and it must be stopped. It weakens employees' basic rights and would impact everybody using information networks," Anton Tamminen, one of the demonstration organisers, told AFP.

The new data retention law has been hotly debated in Finland, in particular after the Helsingin Sanomat newspaper reported Sunday that mobile phone giant Nokia had threatened to leave Finland unless the law was introduced.

Nokia has rejected making such claims.

The name Lex Nokia refers to a case in which the mobile phone maker asked police to investigate whether some of its employees had emailed classified information to a Chinese competitor.

Media questioned whether Nokia had breached existing laws by trying to find proof for their suspicions, but police said Nokia had done nothing wrong. The law currently allows companies in some cases to analyse network traffic data.

Those opposing the new law say people's right to confidential communication would be infringed upon if companies, schools, libraries and telecommunication operators that provide information networks are allowed to monitor what people do on their computers.

The law would not allow providers to read all emails.

"We would have to monitor that the law is not broken when monitoring traffic data and it would be a huge and difficult challenge," ombudsman Reijo Aarnio noted.