China's internet companies have blocked users from sharing a lengthy article written by former Premier Wen Jiabao in tribute to his late mother, in an unexplained act of censorship against a senior member of the ruling Communist Party.

The obituary-style article written by Wen about his mother, who died recently, appeared in a small weekly newspaper called the Macau Herald on Friday and was posted on a public account on Chinese chat app WeChat on Saturday, but was swiftly restricted.

The heartfelt tribute includes details of Wen's mother's struggle during periods of upheaval in China, including the second Sino-Japanese War and the political purges of the Cultural Revolution.