BEIJING » Members of the Chinese elite, including some of the country’s most politically connected figures, have set up a large number of offshore companies that allow them to conceal billions of dollars abroad, according to a new report released Wednesday by the International Consortium of Investigative Journalists, a Washington-based group that works with a number of news organizations around the world.

The report’s authors say it is based on leaked documents concerning tens of thousands of tax-haven clients. The report names more than a dozen of China’s wealthiest people, as well as relatives of top officials, including those of the country’s leader, Xi Jinping; the former premier, Wen Jiabao; and the descendants of the ruling Communist Party’s revolutionary founders.

The report was released at an awkward time for Xi, who has made cracking down on corruption and reining in officials’ displays of wealth among his top priorities since taking charge of the Communist Party in 2012. The combination of wealth and power illustrated in the report could become a political liability for the government at a time when the Chinese public is increasingly concerned about official privilege.

During a regular news briefing, a Foreign Ministry spokesman who was asked about the report dismissed it as "hardly convincing," and suggested that those who leaked the documents had ulterior motives. Censors blocked access to the consortium’s online report in much of China on Wednesday, and Chinese media made no mention of it.

Offshore bank accounts, trusts and shell companies are not in and of themselves illegal, and individuals and companies who move wealth overseas are not necessarily seeking to launder money or avoid tax liability. The Chinese government allows Chinese investors and executives to hold stakes in domestic companies like the Internet giants Baidu and Tencent through offshore investment vehicles. And foreign banks and private equity firms have often encouraged Chinese investors to hold some assets offshore, especially stakes in companies that plan to list their shares in Hong Kong or New York.

"It was us, the foreigners, that imposed this," Rocky Lee, the head of the Greater China corporate law practice of Cadwalader, Wickersham & Taft, told the consortium about the practice. "It had to do with the foreign investors’ general discomfort with Chinese rules and regulations."

But offshore companies can also be used to launder money, dodge taxes and hide an individual’s stake in a company.

China’s widening wealth gap has thrown into stark relief the windfalls enjoyed by the country’s well-connected and privileged elite, especially the relatives of people in powerful posts. The potential for embarrassment is likely to grow as the consortium releases more data and analysts tease apart the strands of previously opaque financial arrangements. The consortium said it would publish a database of tax-haven documents Thursday.

The Chinese government does not require its officials to publicly disclose their financial assets.

The thousands of names disclosed in the report include more than a dozen scions of China’s so-called red nobility, the hallowed revolutionary figures who played pivotal roles in establishing the People’s Republic. Those named include Deng Jiagui, a wealthy businessman who is the brother-in-law of Xi, and Li Xiaolin, the daughter of the former premier Li Peng. Others cited in the report include Wu Jianchang, the son-in-law of Deng Xiaoping, the reformist leader who ushered in China’s embrace of market economics.

Also included are the son, daughter and son-in-law of Wen, the recently retired premier, whose family’s immense wealth was the subject of a series of articles in The in 2012. The investigation found that relatives of Wen held at least $2.7 billion in assets, often through hidden stakes in Chinese financial, telecom and jewelry companies.

The records released by the consortium Wednesday show, for instance, that in 2004 the family of Wen registered a British Virgin Islands company called Fullmark Consultants Limited. Last year, JP Morgan turned over documents to federal investigators in the United States showing that between 2006 and 2008 the bank paid $1.8 million in consulting fees to Fullmark for work done by Wen’s daughter, Wen Ruchun, who worked for JP Morgan under the alias Lily Chang.

In its report, the consortium said Fullmark was controlled by Liu Chunhang, Wen Ruchun’s husband. In 2006, according to the report, he became a government official at the China Banking Regulatory Commission and transferred his stake in Fullmark to Zhang Yuhong, a longtime Wen family friend and business partner.

The Wen family could not be reached for comment Wednesday.

Other records released by the consortium reveal that Xi’s brother-in-law is a half-owner of Excellence Effort Property Development, a British Virgin Islands company. The records say the other half is owned by another company based there, which in turn belongs to Li Wa and Li Xiaoping; the consortium described them as "property tycoons who made news in July by winning a $2 billion bid to purchase commercial real estate in Shenzhen."

The report was released hours before the opening of trial in which Xu Zhiyong, a legal scholar, is accused of "assembling a crowd to disrupt order in a public place." Xu is one of several activists who have called for the public disclosure of officials’ assets. At least eight members of their group, New Citizens Movement, are expected to stand trial in the coming days in what is widely seen as an effort by the government to shut down their grassroots anti-corruption campaign.

The report says that PricewaterhouseCoopers, UBS and other Western banks and accounting firms act as middlemen to help Chinese clients set up trusts and companies in the British Virgin Islands, Samoa and other offshore centers usually associated with hidden wealth. For instance, the giant Swiss financial company Credit Suisse helped Wen’s son, who is also known by the name Winston Wen, to create a company in the British Virgin Islands while his father was premier.

The files that undergird the report, part of a cache of 2.5 million documents leaked to the consortium, originated with two offshore firms that help clients create offshore companies, trusts and bank accounts: Portcullis TrustNet, based in Singapore, and Commonwealth Trust Limited, based in the British Virgin Islands.

The consortium said that more than 50 reporting partners in Europe, North America, Asia and elsewhere were involved in helping it sift through the cache of documents.

The consortium is a project of the Center for Public Integrity, which links journalists around the world for investigative reporting projects. Working with media organizations including The , it has published reports based on the leaked documents that identified a range of prominent figures in other countries who have benefited from overseas accounts. Those include a former budget minister in France, a daughter of the former Philippine dictator Ferdinand Marcos and Azerbaijan’s ruling family.

Files on people from China, Hong Kong and Taiwan — more than 37,000 names — formed the biggest portion of the collection of tax-haven documents, the consortium said. A reporting team spent six months looking through those files. A mainland Chinese news organization that originally participated in the reporting was forced to withdraw from the project after government warnings, the consortium said. It did not name the news organization "to protect journalists from government retaliation."

The Guardian, the British newspaper, said its website was partly blocked in China on Wednesday after it published a report based on some of the leaked tax-haven documents.

© 2014 The New York Times Company