China on Tuesday sentenced a rights activist to five years in prison after convicting him of subversion for compiling documents, including a list of children who died in the 2008 Sichuan earthquake, supporters said.

Tan Zuoren had also produced an independent report on the collapse of school buildings that killed many of the children in the quake, cooperating with other activists, including Ai Weiwei, a leading Chinese artist and architect.

The court in Sichuan's capital, Chengdu, declined to confirm the sentence.

'Tan Zuoren, today every one of 5,000 orphans is your child; they are all calling out for you,' Ai said in his blog on the popular website Twitter.

Ai underwent surgery in Germany late last year for a cerebral haemorrhage that he said was caused when he was beaten by police in Chengdu while he was supporting Tan during his trial in August.

Tan is the second activist sentenced in Chengdu on charges linked to the deaths of children in collapsed school buildings during the earthquake, which killed at least 80,000 people.

In November, activist Huang Qi was sentenced to three years in prison for 'illegal possession of state secrets', a charge apparently linked to his reports of protests by parents of children killed in the earthquake.

Poor construction is believed to have led to the collapse of many school buildings, causing the deaths of 5,335 children, according to the government. Parents and activists said the number is much higher.

In an apparent reaction to the wave of public outrage over the large number of schools that collapsed during the quake, the government announced in May that all school buildings must be reinforced to withstand earthquakes.