Chinese institutions outnumbered Japanese for the first time in the annual Times Higher Education Asia University Rankings, released Thursday.

While the University of Tokyo retained its crown as the region's best, Japan "has lost ground overall, taking 19 of the top 100 positions, down from 20 last year," the rating body said.

"By contrast, mainland China has increased its presence in the prestigious league table, taking 21 places, up from 18 last year," it said.

The result underlines China's rapid growth over the last few decades, including its investment in the education sector.

It also emphasises the increasingly inward-looking trend some commentators see in Japan as fewer young people go abroad to study and as China overtakes it as the destination of choice for foreign students.

China has overtaken Japan as the most-represented nation in the Asia University Rankings 2015. Photo Courtesy: Twitter/@THEworldunirank

The rankings are based on 13 indicators, including the learning environment, volume and reputation of research, citations and international outlook.

South Korea came third in the rankings, with 13 universities, while Taiwan was fourth with 11 institutions.

Six universities from Hong Kong and one from Macau were in the top 100.

By institution, the National University of Singapore ranked second and the University of Hong Kong ranked third, the same spots from last year.

Tellingly, China's top-ranked institutions gained ground, with Peking University taking fourth place and Tsinghua University fifth.

Japan's second-best institution, Kyoto University, came ninth, and Tokyo Institute of Technology 15th, both down two notches from last year.

In contrast, China has made significant progress, with Sun Yat-sen University (42nd) securing a top 50 spot, rising 14 places, while Shanghai Jiao Tong University (39th) jumped eight notches.

There was no immediate comment from China's two top-ranked universities.

The University of Tokyo declined to comment on the result, but its newly appointed president Makoto Gonokami told the ranking body he will develop new academic disciplines and promote cooperation between the state, industry and academia to reverse Japan's decline.

"I want to make our institution a place where students and researchers can experience the excitement and joy imparted by knowledge gained, while conducting cutting-edge research," he was quoted as saying.