First-half growth in the ranks of Chinese Internet users slowed to the weakest pace since the late 1990s, said a quasi-government organization, even as the number of micro-blogging users soared.

The number of Internet users hit 485 million at the end of June, up 6.1 percent half-on-half, the China Internet Network Information Center (CNNIC) said on Tuesday.

In contrast, the number of micro-blogging (Weibo) users grew more than 200 percent to 195 million during the same period. That number was equivalent to 40 percent of China's total online population.

The CNNIC launched its first semi-annual report on China's Internet industry in 1997.

"The slowdown in the growth rate (of Internet users) started last year, but it became pronounced recently," said CNNIC in the report.

It said the deceleration in the growth rate of total users mainly reflected the weak online skills of China's huge population of rural and older people, most of whom don't know how to use a computer.

The number of group-buying users rose 125 percent to 42.2 million, compared with 18.7 million at the end of 2010.

About one-third of the Chinese Weibo users access such sites on their cell phones, said CNNIC.

Sina Corp, Tencent Holdings Ltd and Baidu Inc are the major players in the Weibo space, accounting for more than 90 percent of the market, according to a recent study by RedTech Advisers.

The rapid rise in the popularity of Weibo sites has had a negative effect on traditional social network sites such as Renren Inc, Tencent and Kaixin001.

According to CNNIC data, the user base of China's social-networking sites contracted to 230 million in the first half from 235.1 million at the end of last year.

Despite the slowdown in the growth of the total number of Web users, CNNIC on Tuesday said growth is expected to rebound as a result of the Chinese government's efforts to promote fourth-generation telecom networks and the three-network convergence, which allows telecom carriers, TV broadcasters and Internet companies to enter each other's respective fields and provide services.

The organization forecast that China's Internet user population would surpass 500 million by the end of this year, a growth of nearly 10 percent compared with last year.

China's total Internet penetration rate is 36.2 percent, still far behind countries such as the United States, South Korea and Japan, where the Internet penetration rate exceeded 70 percent, according to the website Internet World Stats.