The South African National Editors' Forum (Sanef) has again threatened legal action if a public interest defence clause is left out of the Protection of State Information Bill.

Sanef said on Thursday it was concerned over State Security Minister Siyabonga Cwele's refusal to allow such a defence in the bill.

"Such a clause would enable a journalist, whistle-blower, or citizen who disclosed classified information, if charged, to enter a defence plea of publication in the public interest," Sanef said in a statement.

Last week, Deputy President Kgalema Motlanthe voiced appreciation for Sanef's view that it would be for the courts in every case to decide whether the public interest defence held.

He suggested this created the basis for a "meeting point" on the issue, sparking hopes that such an amendment could be considered for the bill, Sanef said.

Despite this, Cwele told the National Assembly on Wednesday that the African National Congress could not support such a defence.

"He stated that no other country had such a clause in similar legislation, quietly ignoring the fact that the United States and other countries have other mechanisms in their legislation to provide the protection sought."

Sanef also took strong exception to Cwele's assertions that "foreign spies" were paying civil society groups to oppose the bill.

"Sanef is one of the groups that oppose the bill and rejects the minister's claims as insulting and libellous."

Sanef noted Cwele's admission that following sustained pressure by critics, many amendments had been made to the bill.

These improvements had been based on well-thought out arguments and reasons.

"Sanef not only rejects Cwele's wild allegations but calls on him to provide the proof to back them."

If Cwele's latest obdurate stand prevailed and the bill was passed without the safeguard, Sanef and other critics would have no alternative but to press for the legislation being referred to the Constitutional Court for it to rule on its constitutionality.

"The alternative is that important information will be withheld from the public," Sanef said.