Chinese websites have blocked searches for "Fatty Kim the Third", as many Chinese mockingly call North Korean leader Kim Jong-un, with China's Foreign Ministry saying it did not approve of ridiculing foreign leaders.
Chinese internet users began reporting last week that searches on the Twitter-like microblogging site Weibo and search engine Baidu for the expression returned no results, the normal sign that something is being blocked despite its wide usage.
The term - which refers to the weight of Mr Kim, his father and grandfather - was last blocked in September after neighbouring North Korea's latest nuclear test.
Mr Kim is unpopular in China because of his country's repeated nuclear and missile tests.
Kim Jong-un's father Kim Jong-il, or 'Fatty Kim the Second' (Reuters)
Chinese Foreign Ministry spokesman Geng Shuang said reports the government had banned the search term "did not accord with the facts".
"What I want to stress is that China has always dedicated itself to constructing a rational, cultured and healthy environment for public opinion," Mr Geng told a daily news briefing.
China "does not approve of insulting or ridiculing language to address any country's leader", he added, without elaborating.
Both Baidu Inc and Sina Corp, which owns Weibo, declined to comment.
China's internet regulator did not respond to a request for comment.
Kim Il-sung, Kim Jong-un's grandfather (Reuters)
Many Chinese, however, took to Weibo to suggest multiple other terms which sound similar to "Fatty Kim the Third" and which are not blocked.