A Chinese court sentenced an octogenarian critic of the Communist Party and his assistant to suspended prison terms and fines Wednesday, one of their lawyers said, decrying the case as "inherently flawed".

Tie Liu, an 81-year-old writer whose real name is Huang Zerong, was given two and a half years in jail with a four-year reprieve for "running an illegal business", attorney Liu Xiaoyuan told AFP.

Tie was also fined 30,000 yuan ($4,800).

His assistant Huang Jing was handed a one-year sentence with a one-year reprieve and fined 5,000 yuan ($800) on the same charge.

The suspended sentences mean that the two will not be sent to prison, although it was not clear whether they would be released immediately.

"This case is inherently flawed," Liu told AFP, condemning the authorities' decision to try the case in Tie's home town of Chengdu.

The city, the capital of Sichuan province in the southwest, is some 1,800 kilometres (1,100 miles) from Tie's residence in Beijing.

"The Sichuan court has no jurisdiction over this case," Liu said. "If they're going after him for 'conducting an illegal business', everything he's published has been in Beijing. So why is he being tried by a court in Sichuan?"

Tie, who turned 81 last May, has long been a thorn in the side of the Communist Party.

As a young journalist critical of Mao Zedong, founding father of the People's Republic, he spent more than 20 years in labour camps before being rehabilitated in 1980.

More recently he edited a privately-distributed magazine entitled "Scars of the Past".

Tie's wife has said she believes her husband has been targeted because of a critical essay he wrote about top Communist Party propaganda official Liu Yunshan.

International groups, including the PEN American Centre, have criticised Tie's prosecution and called for his immediate release.

The verdict comes amid a broad crackdown on dissent in the two years since President Xi Jinping rose to power, with dozens of journalists, human rights activists, lawyers and others rounded up.

Tie was initially taken away by Beijing police last September for "picking quarrels and provoking trouble", a nebulous charge increasingly used to silence critics of the ruling party.

But the charge was later dropped.

"The prosecution did not pursue the 'picking quarrels and provoking trouble' charge," Liu wrote Wednesday on Twitter, quipping: "I suppose we can consider this an improvement?"