The country's four main opposition parties on Wednesday rejected attempts by President Jacob Zuma to defuse the row over his nomination of Judge Sandile Ngcobo as Chief Justice, insisting it was unconstitutional.

The Democratic Alliance (DA), the Congress of the People (Cope), the Independent Democrats (ID), and the Inkatha Freedom Party (IFP) said they remained convinced that Zuma had undermined the law by failing to consult properly with the opposition and the Judicial Service Commission (JSC) before nominating Ngcobo on August 6 to replace retiring Chief Justice Pius Langa.

The opposition has urged Zuma to restart the process from scratch and on Tuesday said they would prefer Deputy Chief Justice Dikgang Moseneke for the post.

Zuma replied in a formal letter on Wednesday, saying that Ngcobo remained his preferred candidate, though he had not "taken a final decision on whom to appoint".

"Please rest assured, that I have not appointed a new Chief Justice, nor have I taken a final decision on whom to appoint as the new Chief Justice," he wrote.

He added that he would "take into account any views the leaders of political parties may express about him [Ngcobo]".

Later, at a meeting with DA Parliamentary leader Athol Trollip, Zuma welcomed the opposition's statement on Moseneke and said the controversy was partly to blame on a simple linguistic accident on his part.

He was referring to a remark he made on August 6 that he had "appointed a judge that I believe is capable" of succeeding Langa.

The opposition claimed that this showed he considered his nomination to be final and their comment to be irrelevant.

The President countered: "It was a slip of the tongue, literally."

He urged the opposition to rather focus on a letter he wrote to them in which he asked for comment on his "nomination" and also apologised for the fact that it reached party leaders a day after the announcement.

"The letters were delayed."

Zuma said he was happy to let the opposition put their case on Moseneke, whom the parties believed was overlooked because he had angered the ruling party.

"That is what I wanted, so they can help me if there are some things I overlooked," Zuma said after a meeting with Trollip.

"It will help me relook, before I take a final decision."

But, the parties were unmoved, saying the remarks were typical attempts by the President to sidestep debate on the real issues at stake.

"The President's response ignores the substantive issues we raised in our letter and attempts to mask his true intent behind superficiality and technicalities.

"This habit - the smoothing over of issues of substance with generic rhetoric - is unfortunately becoming a defining characteristic of the way in which the president engages with civil society and the opposition.

"There is a clear intention to avoid real debate on substantive issues."

They said his letter was "disingenuous" and mocked Zuma's contention that "it is common cause that you first nominate, and then open the consultative process".

It said Zuma had in doing so, narrowed "the scope of any advice he might receive" and the fact that he was not willing to withdraw the nomination, showed that he had made up his mind.

Cope demanded that Zuma withdraw the nomination of Ngcobo if he wanted the position of Chief Justice to be seen as anything other than a political appointment.

"Regardless of what word was used at the time, the point we were making is that the process is flawed," said Cope spokesperson Philip Dexter.

That he announced a name before consulting with the National
Assembly or the JSC showed that he had "no respect" for the opposition.

ID leader Patricia de Lille said it was problematic that Zuma was not asking opposition parties for their preferred candidates, but merely seeking their views on his preferred candidate.

"He's already made up his mind," she said.

The opposition said that Moseneke was the best qualified person for the post because he had been working with Langa for the past four years.

They argue Moseneke has been passed over for promotion because he angered the African National Congress (ANC) in stating, before the ruling party's Polokwane national conference - where Zuma won control of the ANC - that the future of the country did not lie with delegates, but with the electorate.

The parties said they believed the mishandling of the process had victimised Ngcobo "who is by all accounts, an able candidate and certainly one worthy of consideration for the position.

"Because the President has undermined the process surrounding the appointment to the position of Chief Justice, his nomination has been tainted in turn," the parties said in a joint statement.