The newspaper said Beijing swiftly blocked access Friday to its English and Chinese-language websites "from computers in mainland China in response to the news organization's decision to post an article in both languages describing wealth accumulated by the family of the country's prime minister."
In its investigation, the Times said Wen Jiabao has been described in the state media as "the People's Premier" and "Grandpa Wen."
However, the newspaper's Shanghai bureau chief found many of Wen's close relatives including his wife and son "have become extraordinarily wealthy" during his tenure, accumulating shares in banks, jewelers, real estate and telecom companies over which Wen has broad authority and that the "relatives have controlled assets worth at least $2.7 billion."
The report said its bureau chief had collected and reviewed corporate and regulatory documents tied to Wen's relatives, their friends, work colleagues and business partners. No holdings, however, were found in Wen's name.
The Times said China has extensive Internet censorship, monitored by tens of thousands of employees.
Times spokeswoman Eileen Murphy expressed hope that full access to its websites would be restored soon.
The article on Wen and his family comes ahead of next month's Chinese Communist Party's annual congress, which will also mark the country's once-a-decade change of leadership.
China has been hit by a number of scandals as the party strives to preserve its image at home and abroad.