Months of investigation by the auditor-general's office into the terms and procedures of South Africa's complex arms deals will culminate in the tabling of a 10-page document in parliament this week. While it is understood the report is not explosive, it is set to light the fuse for some big bangs.

According to a defence ministry source, the auditor-general has recommended a more detailed investigation - via a forensic audit or special investigation - of the sub-contracts which fell outside his original terms of reference.

It is some of these sub-contracts - between foreign contractors and local defence suppliers - that have attracted most of the allegations of corruption that have dogged the controversial acquisition process.

Among the key areas believed to have been dealt with is the decision, late in the tender process, to move the goalposts on the bidding for a fighter-trainer - a contract which eventually went to British Aerospace's Hawk trainer.

'The auditor-general was not satisfied with such explanations' Defence industry sources say that "one value system" was agreed for the technical evaluation of all defence acquisition programmes - the trainers, the advanced fighter, the corvettes, the submarines and the helicopters.

Essentially, all other things being equal, price was to be the crucial factor.

When it became clear that the Italian ND339 trainer would have to be recommended, the ministry of defence, with cabinet approval, downgraded the price factor for this programme.

According to Helmoed Heitman of Jane's Defence Weekly, there were good reasons for moving the goalposts on the trainer. "The ND339 is cheap, but it's old technology. Essentially, it's an Impala with a new nose. Also it has a straight wing, rather than a swept wing - which is a disadvantage for training for the advanced fighter."

But it is clear that the auditor-general was not satisfied with such explanations.

Mosiuoa Lekota, the defence minister, could not be reached for comment, but a source close to the ministry said: "The auditor-general's report has not yielded anything new. It found the integrity of process at a government to government level cannot be questioned. However, lower down, at the sub-contract level, there are things that can still be investigated."

With acknowledgement to Sam Sole and the Sunday Independent.