A South African judicial inquiry clearing all government officials of corruption over a multi-billion dollar arms deal was greeted with scorn on Thursday by critics of President Jacob Zuma.

"It's a whitewash," leading anti-arms-deal campaigner Terry Crawford-Browne told AFP. "It is very much as expected."

The opposition Democratic Alliance party called the commission's report "a massive disappointment because those who were implicated in arms deal corruption have effectively been let off the hook".

The four-year inquiry into the scandal, in which Zuma was a suspect, found that there was no evidence to support widespread allegations of bribery, fraud and corruption, the president said Thursday.

Zuma summarised the findings of the commission in a statement in which he said he had received the three-volume report at the end of last year and was now making it public.

Critics have long charged that the government-appointed inquiry was toothless and was being used in an attempt to put the issue to rest.

Paul Hoffman, a lawyer representing anti-arms-deal activists, likened the inquiry to "a farce".

The commission suffered a series of resignations of officials involved, including the departure of one of the three original judges.

- Scandal-hit president -

"The commission states that the widespread allegations of bribery, corruption and fraud in the arms procurement process... have found no support or corroboration in the evidence," Zuma's statement said.

"Any findings pointing to wrongdoing should be given to law enforcement agencies for further action. There are no such findings and the commission does not make any recommendations."

The $4.8 billion arms deal saw the government acquire a vast range of military equipment, including fighter jets, helicopters, warships and submarines from countries including Britain, France and Sweden.

The commission's report comes as a High Court challenge is under way to reinstate more than 700 charges of corruption against Zuma which were dropped in 2009, shortly before he became president.

The charges, which relate to the arms deal signed in 1999 when Zuma was deputy president, were dropped allegedly because of interference in the prosecution case by his political opponents.

Zuma was accused of having accepted bribes from international arms manufacturers.

Zuma's advisor, Schabir Shaik, was jailed for 15 years on related charges in 2005, with the judge saying there was "overwhelming" evidence of a corrupt relationship between the two.

Shaik was released on medical parole in 2009, the year Zuma was elected president.

Zuma set up the commission, headed by Judge Willie Seriti, after Crawford-Browne launched a case for an inquiry in the Constitutional Court.

The president unveiled its conclusions after months of separate corruption controversies that have weakened his position within the ruling African National Congress (ANC) party.

A court ruled last month that Zuma had violated the constitution over spending on his private residence, and he has been beset by allegations that a wealthy family had such influence over him that it could decide ministerial appointments.

Former president Thabo Mbeki, who was in power when the arms deal was signed, was among witnesses who testified at the commission.

Mbeki defended the decision to spend billions on arms despite dire poverty in a country emerging from the apartheid era.

He said the government wanted to reclaim the defence force from the white-minority regime ousted by Nelson Mandela and the ANC in 1994.

The commission found that the purchase of the weapons was "necessary".

The Minister in the Presidency, Jeff Radebe, denied the commission was a whitewash, saying: "We trust these findings will bring final closure to this long drawn-out process."

Crawford-Browne said activists would consider taking the case back to the Constitutional Court.