Lawyers hired by the family of Chen Guangcheng said Friday they had been barred from meeting the blind activist's nephew, who is in police custody facing a charge of "intentional murder".

Chen Kegui is being held after he attacked intruders who broke into his family home in the eastern Shandong province apparently searching for Chen Guangcheng following his dramatic escape from house arrest last month.

Lawyers for the nephew have said a local Communist Party official was injured seriously in the fight in the early hours of April 27 and two others were slightly harmed.

Si Weijiang, a lawyer hired by Chen Kegui's wife, said on his blog that police in Shandong's Yinan county told his colleague that Chen Kegui had applied for legal aid and had been appointed two other attorneys.

"But they did not provide any written documents and refused (colleague) Ding Xikui's demands to meet with Chen and help him choose lawyers," Si wrote.

"Yinan police are suspected of illegally depriving Chen of his right to legal defence, and we deeply regret this."

The online posting was confirmed as real to AFP by Si's assistant, who added he was not taking media interviews. Ding also confirmed the news when reached by phone.

Chen Guangcheng, whose escape from his home in Dongshigu village -- which comes under Yinan county -- and subsequent flight to the US embassy sparked a diplomatic crisis, has strongly condemned his nephew's detention.

The blind activist had been held under extra-judicial house arrest since he was released from a four-year jail sentence in 2010, and he is now in a Beijing hospital with his family awaiting permission to go to the United States.

It is unclear whether the official who was seriously injured on April 27 has died or not, but Ding told AFP the charge of "intentional murder" can include attempted homicide in China.