President Tarja Halonen signed the controversial bill on data protection for electronic communications into law on Friday.
Earlier in the month, Parliament had passed the measureby a vote of 96 to 56. The most controversial aspect of the law is that it allows employers to check whom employees have corresponded with through their company e-mail accounts.
Companies are also to be given legal access to information on the size of the e-mails and whether or not attachments were involved. However, reading the contents of the messages themselves is not permitted under the new law.
The aim of the new law is to help prevent corporate espionage. It was given the name Lex Nokia because of intense lobbying by Nokia for its passage.
Last-ditch attempts by opponents of the measure to persuade the President not to sign the bill failed.
The law comes into effect at the beginning of June.
When it passed the bill, Parliament added a statement calling for a follow-up on how well the aims of the measure have been realised.
The Ministry of Transport and Communications is required to report to the Parliamentary committee on transport and communications on the matter by the end of 2010.
Another statement passed by Parliament states that possible shortcomings or confusion in police authority in the investigation of violations of corporate secrets and crimes should be examined speedily, and if necessary, already before a broader reform on legislation on coercive measures.
