Sina Weibo's new regulations took effect Monday and would suspend a user for two days for posting content five or more times containing politically sensitive words or images. The company says if the information is viewed as being spread maliciously, the account may be deleted altogether.
China's Internet companies are pressured to control information or risk losing the right to operate profitable businesses in a fast-growing market.
In late March, Sina Weibo banned commenting for three days amid a high-level political crisis.
The Twitter-like site has more than 300 million registered users.