LONDON - Rich nations' efforts to tighten rules on patents and copyrights are unlikely to benefit those in poor countries and will make it harder to reduce poverty, a government-commissioned report warned Thursday.

While strict laws on intellectual property benefit companies in the pharmaceutical, software and entertainment industries, among others, they can cause hardship in the developing world by boosting prices for some essential goods, said the commission.

Medicines, seeds and computer programs are among the products affected.

The Commission on Intellectual Property Rights, appointed by International Development Secretary Clare Short, urged wealthy countries to consider the needs of poorer nations while pushing for rules that help their own industries.

"Every bit of intellectual property is something that creates an incentive for one group and a cost for another group, and you need to make that balance wisely and well," said Stanford University law professor John Barton, the commission's chairman. "In the long term we're better off if we have a more economically robust developing world."

Advocates of strict patent and copyright rules say they encourage innovation by ensuring that those who come up with useful ideas are able to profit from them. Wealthy nations including the United States have encouraged poorer ones to tighten their rules.

But the commission said such notions should not be imposed on poor parts of the world, where they can do more harm than good.

"We really need to think about the developing countries' needs when we tighten up the systems to try to protect the understandable concerns of the movie industry and the computer software industry and the music industry," Barton said.

Tight copyright restrictions put in place to protect the entertainment industry from a flood of pirated films and CDs could also raise the prices of teaching materials and deprive those in poor countries of the benefits of the Internet by restricting access to scientific journals, databases and other useful information, he continued.

Among the commission's recommendations were the suggestion that companies sell patented and copyrighted items more cheaply in poor countries than in the developed world.

Protecting patents and copyrights "raises prices on things like drugs, computer programs, seeds, and that's exactly how it's supposed to work," he said. "But the question is how equitably to share those prices increases and share the costs of the research between rich countries and poor countries."