China's communist party appears to be fiercely debating whether to put Bo Xilai on criminal trial for trying to protect his wife from murder charges, analysts said Thursday.

If he is prosecuted, they suggested the man who was once one of China's most high profile politicians, tipped for a place on the country's top decision-making body, was likely to escape the most serious possible charges.

The comments came after the state-run news agency Xinhua released a detailed and lengthy report on the trial of Wang Lijun, Bo's former right-hand man, for defection, bribery and other offences.

It said Wang briefed the "main person responsible" for the Chongqing Communist party committee -- which Bo headed -- about the suspected role of the politician's wife Gu Kailai in the murder of British businessman Neil Heywood.

Wang was later rebuked and fled to the US consulate in Chengdu seeking asylum, blowing the scandal wide open and triggering Bo's fall from grace, while exposing deep divisions in China's ruling communist party.

Bo has not been seen in public for months and he faces an internal party investigation for "serious" violations of discipline.

The Xinhua account did not identify Bo by name, but implied he knew his wife was suspected of Heywood's murder.

Under Chinese law sheltering a criminal carries a maximum punishment of 10 years in prison.

But the fact that Bo's name was not mentioned indicated the Party had yet to reach consensus about how to deal with him, said Bo Zhiyue, a Chinese politics expert at the National University of Singapore -- who is not a relation.

"The wording is intentionally vague, to leave room for the (communist party's) central committee to manoeuvre." he told AFP.

"Bo is very popular, not just amongst the people but also amongst certain elites, so (party authorities) have to be very careful," he said.

Willy Lam, politics expert at the Chinese University of Hong Kong, added: "There is still a power struggle going on, I think Bo still has powerful patrons... who are applying pressure to spare Bo from criminal charges."

While divisive, Bo retains some public support, which was to be seen at this week's anti-Japan demonstrations over disputed islands. "Diaoyu belongs to China, Bo Xilai is of the people", read one banner in Sichuan province.

If Bo stands criminal trial, he would become the second member of China's powerful Politburo in the last decade to face criminal proceedings.

Chen Liangyu, a former Communist Party chief of Shanghai, was jailed for 18 years in 2008 after being convicted of abuse of power and accepting bribes in a trial that had wide political overtones.

Court accounts and official news reports on Gu's and Wang's cases did not implicate Bo in the more serious offences of bribery and murder, which can both carry the death sentence.

"I think there will be criminal proceedings... now that the charge of covering up a murder has been confirmed," Zhang Ming, a professor of politics at the People's University in Beijing told AFP.

But he added: "I don't think there will be any additional charges. I expect he'll get a prison sentence of about 10 years."

Gu was last month convicted of Heywood's murder and given a suspended death sentence, which is normally commuted to life imprisonment in China.

Xinhua quoted Wang as saying at his trial: "I acknowledge and confess the guilt accused by the prosecuting body and show my repentance."

In an editorial on Wang's trial which mentioned Bo by name, the state-run Global Times called for more "criminal officials" to be "firmly punished".

"Justice can be found anywhere...this is true not only in Wang's case but for many powerful elites," it said.