Five people are under investigation over the leaking of national economic data, the Beijing People's Procuratorate said yesterday.

One of the five is an official working at the National Bureau of Statistics' secretary office, China News Service reported, citing Zhang Huawei, director at the prosecutors office.

Zhang did not disclose the titles or names of the people involved, saying only that they came from different government departments.

At a press conference last week to unveil May's economic data, bureau spokesman Sheng Laiyun condemned the leaking of key data. He said then that one official at the bureau had already been put under investigation.

Suspicion that data was being leaked arose last year after the Reuters news agency had accurately reported China's consumer prices before their official release seven times over the past two years. They cited unidentified sources or unnamed key government officials. Reuters was dubbed China's "Octopus Paul" after the octopus who had "predicted" Germany's results in the soccer World Cup last year.

In its latest prediction, Reuters said May's consumer price index would be 5.4 percent, just 0.1 percentage points short of the actual figure.

Bloomberg and Morgan Stanley successfully predicted the May inflation rate, quoting a survey of economists and analysis of public documents.

Sheng said the bureau would be taking steps to safeguard economic data before its release, including the possibility of shortening the period between production and release.

But Sheng also accepted that some institutions could successfully estimate the data without leaks being involved.

The leaking of economic data is considered serious because it allows speculators to anticipate stock market movements.