Nearly 28 million netizens have quit using micro blogs in China over the last year, a once popular social network platform that had accumulated more than 500 million accounts over the last four years, an industry report said.

Micro blogs were facing strong challenges from smartphone-based instant messaging applications such as WeChat, said China Internet Network Information Center.

Other social networking websites were also facing "substantial" user number losses in 2013, it said.

Sina Corp, Tencent Holdings Ltd are the top micro blog providers in the country.

China had about 280 million micro blog users in 2013 while WeChat claimed to have 600 million users globally.

China has added 64 million instant messaging users in last year, pushing the total amount to 532 million, according to CNNIC.