European lawmakers are preparing to vote on a directive which could protect companies' computerised inventions.
Protesters gathered outside the parliament for the vote
The proposed law, the Computer Implemented Inventions Directive, has been a bone of contention since 2001.
Opponents say it would lead to the patenting of software, which is already protected by copyright.
This would harm small firms and open source developers. Supporters say programs that make other technologies work need more protection.
The proposed law has undergone several amendments from its original form, or "Common Position."
The vote on Wednesday in the European Parliament will be on the amendments which were agreed upon by the European Council in May.
On Monday, key representatives from several big technology firms said opposed the changes.
Consumer interest groups have added several more amendments in recent weeks.
They say the European Members of Parliament should vote in favour of the key amendments.
If the law is eventually approved, it would mean that there would be an EU-wide patent protection scheme for any computer-based invention, such as programs for medical scanners, mobiles, or ABS car-brake systems.
In other words, it would affect computer programs when the software is used to make an invention or innovation work.
In the US, the patenting of computer programs and net business processes is allowed.
The US-based Amazon.com holds a patent for its one-click shopping service, for example.
Protection and innovation
Protesters began to gather on Tuesday outside the European Parliament ahead of the vote.
More than 1,700 Europe-wide companies, represented by the Free Information Infrastructure UK (FFII-UK), joined the plea for the European Union to reject any law which patents software.
"If we want to preserve a competitive, innovative and successful European IT sector, it is essential that the Council's common position be amended," said Rufus Pollock, director of the FFII-UK.
"We believe the set of 21 compromise amendments being put forward by MEPs from all political groups is what is needed to achieve this goal and to avoid the worst-case scenario of a US-style software patent system.
"As it stands, the current text of the directive will impose software and business process patents across the EU."
But the big technology players remained adamant.
"Any departure from the Common Position would put at risk our future prosperity and significant numbers of jobs across Europe," said Serge Tchuruk, chief executive of French telecoms firm Alcatel.
Philips, Nokia, and Siemens, have also voiced concern over the amendments.
Telecoms firm Ericsson's chief executive Carl-Henric Svanberg said in a joint letter to EU leaders: "If we are not able to patent our computer-implemented inventions, the digital technology industry, and also Europe as a region, will have difficulty staying competitive."
Other big companies, such as IBM and Sun, have voiced their opposition to the proposed law.
Many fear that the law would suffocate innovation and openness to research and development within smaller companies that have less legal power.
Larger, more powerful companies would be able to collect patents on software processes.
After Wednesday's vote, the Council has three months to consider the decision. If it then votes to reject it, Parliament and the Council would go to a conciliation process to come up with an agreement.
The directive could be abandoned if that process failed.