For books and academic journals, the law takes a different approach. If a firm copies more than a quarter of a book or journal, or an entire journal article, a limit on the retail value of the copied book or journal kicks in.

If a firm makes so many copies that the retail value of the books or journals copied over six months is more than HK$6,000, it will be in breach of the law. For example, a firm might want to make copies of more than a quarter of a book that sells for HK$600; it will break the law if the number of copies exceeds 10.

A government spokesman said the law would come into force in four to six months' time. Between now and then, it will work to make businesses aware of the limits.

Dillys Yu Ka-po, general manager of the Hong Kong Copyright Licensing Association, which represents major book and journal publishers in Hong Kong, welcomed yesterday's Legislative Council vote.

'We believe the law will enhance copyright protection,' she said. 'We hope the regulations will come into effect as soon as possible.' The problem of unauthorised copying and distribution of copyrighted works was serious, she said.

The Copyright Ordinance was amended more than two years ago to make it an offence for businesses to copy copyrighted work excessively. But it has taken until now to pass a second amendment that sets out what constitutes excessive copying.

The limits were drawn up after negotiation between the government and stakeholders such as the association and the Hong Kong Reprographic Rights Licensing Society.

Secretary for Commerce and Economic Development Rita Lau Ng Wai-lan said the government would soon start publicising the rules and educating businesses about them.