Johannesburg - Fair game or cheap shot? In a case recalling the Danish caricatures of the Muslim Prophet Mohammed, a cartoonist in South Africa is taking heat over his controversial depiction of African National Congress leader Jacob Zuma.

The offender is award-winning South African cartoonist Jonathan Shapiro, aka Zapiro, whose hard-hitting, often hilarious political doodles have chronicled the country's at-times wobbly trajectory since democracy in 1994.

Zuma, who trounced President Thabo Mbeki in a vote for ruling party leader in December, has been one of Zapiro's favourite subjects since his infamous rape trial in 2005.

The former deputy president was acquitted of the charges but his extraordinary revelation that he had taken a shower to prevent infection after unprotected sex with his HIV-positive accuser earned him a shower head on his bald pate thereafter in Zapiro's cartoons.

At the weekend, the cartoonist cranked up the criticism a notch. His weekly contribution to the Sunday Times - the country's largest-selling newspaper - featured Zuma poised to "rape" the justice system, with the help of his political allies.

Zuma, sprinkled by the requisite showerhead, is shown unbuckling his trouser belt as ANC secretary-general Gwede Mantashe and the leaders of the allied trade union movement, Communist Party and ANC Youth League pin down a woman representing the justice system.

"Go for it boss," Mantashe exhorts.

Framing the cartoon is the "Stalingrad-like" campaign by Zuma's allies - an analogy used by Zuma's lawyer - to have charges of corruption, fraud and racketeering against him dropped in advance of general elections next year.

Zuma is the ANC's candidate to succeed Thabo Mbeki as president after the election, if, as appears likely, the ANC wins the day. A trial on the charges arising out of a state arms deal is seen as the only real hurdle to the 66-year-old reaching the top office.

On Friday, Zuma returns to court in the eastern city of Pietermaritzburg for the ruling in his application to have the case thrown out on the basis that prosecutors failed to follow proper procedure in indicting him.

As with his past court appearances, crowds of his supporters will be bussed in a mass show of support.

In the meantime, the leaders of the tripartite governing alliance - the ANC, trade union congress COSATU and the Communist Party - have been intensifying their attacks on the prosecution and the judiciary in a bid to pressure them to abandon the case.

Zuma's supporters say he is being "persecuted, not prosecuted," despite evidence he was on the take from Schabir Shaik, a convicted fraudster who benefited from the arms deal.

"Counter-revolutionaries," was how Mantashe described judges presiding over one of Zuma's multiple pre-trial challenges in July. Other alliance members have rubbished judges as drunks.

ANC Youth League president Julius Malema declared he was willing to "kill for Zuma" rather than let him face trial.

"I'm angry, I'm outraged - and there are many others in the country and the world - about what Jacob Zuma is trying to do with the justice system," Shapiro told SAfm public radio Tuesday.

"Zuma is about to rape the justice system with the help of his political allies," he said, denying he was making a link with the rape case.

An equally outraged ANC alliance said the cartoon bordered on "defamation of character" and demanded an apology.

Some found the rape imagery unfortunate in a country with one of the world's highest rape rates - over 130 reported cases a day. Others found it appropriate.

Many, including the opposition Democratic Alliance (DA) and many media analysts, welcomed Shapiro's contribution to the Zuma debate.

An unfavourable ruling in the Pietermaritzburg High Court Friday would not necessarily spell an imminent trial for Zuma. If unsuccessful in Pietermaritzburg, he is expected to move for a permanent stay of execution.

Speculation has also been swirling that the ANC might be tempted to push for a change in the constitution to give him immunity from prosecution if he still faces trial after becoming president.

The ANC has denied that option is on the table as yet.