Jan 11 - China has arrested more than 4,000 people for violating intellectual property rights (IPR) since November and will enforce tougher punishments to combat the "rampant" problem, a senior government official said on Tuesday.

A counterfeit Gucci jacket is on sale for 50 rmb (5 euros) at a market in China

Gao Feng, deputy director of the Ministry of Public Security's Economic Crimes Investigation Bureau, told a news conference that his agency had uncovered more than 2,000 cases since China launched a six-month campaign to beef up enforcement of intellectual property rights last November.

The financial value of the cases totalled 2.3 billion yuan ($348 million), Gao said, adding that the number of arrests, cases and financial value represent a tripling from the same period a year ago.

"On one hand they demonstrate the achievements we've made in cracking down on the violation of IPR, on the other hand it also indicates that IPR violation is still quite rampant and frequent," Gao said. "So we want to introduce heavier punishments."

China's lax enforcement of intellectual property rights could feature in trade talks between U.S. President Barack Obama and his counterpart Hu Jintao, when the Chinese president visits the United States next week.

Under mounting pressure from the United States, China has vowed harsher punishment of copyright piracy, responding with a six-month campaign aimed at counterfeit books, music, DVDs and software, in an effort to show that the country is serious about tackling the problem.

China has promised "concrete results" from the latest crackdown, but U.S. groups say a sustained effort is necessary to achieve real results.

Despite China's campaign and repeated vows to get tough, pirated goods remain widely available on Chinese streets and in shops, sometimes sold within sight of large propaganda posters denouncing IPR violations.

The International Intellectual Property Alliance, which represents U.S. copyright industry groups, has estimated U.S. trade losses in China due to piracy at $3.5 billion in 2009.

U.S. customs officials say 80 percent of the fake tennis shoes, clothing, luxury bags and other goods they seize each year at the border come from China.

(Reporting by Sui-Lee Wee; Editing by Ben Blanchard and Alex Richardson)