Two non-governmental organisations (NGOs) intend applying to the High Court in Pretoria to have the "unsustainable" charges against Finance Minister Pravin Gordhan scrapped.

Freedom Under Law and the Helen Suzman Foundation sent a letter of intent to National Director of Public Prosecutions Shaun Abrahams on Friday, calling for him to withdraw the charges against Gordhan.

Failing that, they wanted the National Prosecuting Authority (NPA) to deliver its documents and certain details about the case to them by October 21, with a view to stopping Gordhan's prosecution.

"Ordinarily, one does not comment on the merits of pending court cases," former Constitutional Court judge Johann Kriegler, of Freedom Under Law, said on Friday.

"But we cannot stand by while untold damage is being done to the reputation and stability of our country following the shocking allegations levelled at the Minister of Finance and the theatrical manner in which they were broadcast earlier this week."

Kriegler said the two NGOs had the charges analysed and were advised that they were legally flawed and factually unfounded.

"It is not for us to speculate who or what, if anything, lies behind the investigation and prosecution, but we have been advised that there is a basis upon which we can ask the High Court to examine the validity and viability of the charges with a view to cutting short the prosecution."

The two organisations gave the NPA until 16:00 on Friday, October 21, to withdraw the charges against Gordhan, or provide the documents to them.

Abrahams announced on Tuesday that Gordhan, former Sars deputy commissioner Ivan Pillay and former commissioner Oupa Magashula would be charged in relation to an early retirement pay-out granted to Pillay in 2010, and the extension of his contract.