Former Scorpions boss Leonard McCarthy has indicated it was acting National Prosecuting Authority boss Mokotedi Mpshe's decision to charge African National Congress leader Jacob Zuma with corruption and not his.

In a letter to Mpshe, McCarthy declines to answer further questions about the matter.

Earlier this week Mpshe announced that McCarthy and former prosecuting authority boss Bulelani Ngcuka abused the NPA?s processes in deciding to prosecute Zuma.

The acting National Director of Public Prosecutions also read out transcripts of conversations between Ngcuka and McCarthy.

The conversations were secretly recorded by the National Intelligence Agency.

Ngcuka has also hit back at Mpshe, saying he was never party to any conspiracy to frustrate Zuma?s political ambitions.

He added it was disturbing and inexplicable that he never had the opportunity to view the transcripts which were made available to the media this week.

The former NPA boss confirmed he was approached by Zuma's prosecuting team a week ago to respond to certain questions.

He said he was informed that he was approached by the NPA as a possible witness, in the event Zuma brought an application for a stay of prosecution.

Ngcuka declined to sign a sworn statement as he had no access to the transcripts and he was unsure if the recordings were legally obtained.

Ncguka said the selective use of extracts of the discussions confirmed his worst fears about a potential ambush. But he said would only respond to the allegations once he had full access to independently authenticated recordings.