SHANGHAI — A multilateral treaty to protect the intellectual property rights of thesps and warblers the world over is due to be signed in Beijing next week, although regulators say enforcing the agreement will require hard work.Once it is ratified, the treaty “will strengthen the economic rights of performers and provide potential extra income from their work,” Trevor Clarke, assistant director general of the World Intellectual Property Organization, told a copyright forum in Beijing. As it stands, payment for a thesp’s work, and intellectual property protection, are not included in international copyright law, unlike that of helmers, screenwriters and musicians. This means thesps whose movies or performances are sold abroad do not have a legal right to payment, and if any payment is made, it goes to the producer. They also have no recourse in many countries if their work is manipulated in any way that may harm their reputation. The plan to sign the treaty in China is significant because it has a terrible record when it comes to IP protection and is regularly slammed by the U.S. and the European Union for its lax enforcement of copyright law. Yu Cike, director general of the copyright department of China’s National Copyright Administration, welcomed the new rules. “In the era of the Internet, protection of performers’ IP rights is still lacking globally. The expected treaty mainly addresses this issue,” Yu said in the China Daily newspaper. It has taken more than a decade for WIPO, which is part of the United Nations, to come up with the treaty. An agreement between the U.S. and European Union last year paved the way for concluding the pact, although it still needs to be ratified by the 185 member states.