China's government investors more than doubled their investments in major Japanese blue-chip companies in 2010, the Wall Street Journal said, citing investment advisory firms and people familiar with the matter.

The combined stakes of China's sovereign investors in those companies topped 1.6 trillion yen ($19.4 billion), the paper said, adding the stakes were mostly bought through Australian-registered investment vehicles.

The Chinese investors, who appear to be passive stake holders in the companies, are silent on matters of corporate strategy and management, the WSJ said.

The stakes highlight China's growing financial clout as well as the growing economic ties between China and Japan, according to the newspaper.