State prosecutor Billy Downer faced an array of questions from a full bench of the Supreme Court of Appeal on Tuesday on the admissibility of an encrypted fax on the second day of Schabir Shaik's appeal hearing.

The fax details the negotiation of a R500,000 alleged bribe for Jacob Zuma -- while he was deputy president -- for protection in the investigation in South Africa's multi-billion rand arms deal.

"It's a very very probative piece of evidence which could be allowed in," Downer said.

The defence said that even if Alain Thetard, the author of the fax, was not a credible witness, the facts contained in the fax still stood.

The defence contended that Thetard was not a credible witness because he had lied on various occasions and for this reason the fax should not be allowed as evidence.

The State conceded, as it had in the trial, that a court would find him an incredible witness.

"We still sit with the facts. If you look at the statement itself (the fax) what possible motive could Thetard have had in composing a fax that was not true? There is none," Downer asked rhetorically.

Downer said all facts contained in the fax were confirmed and the appeal hearing is continuing.

With acknowledgement to Sapa.