The Democratic Alliance (DA) has ignored the deadline set by President Jacob Zuma for the opposition to comment on his nomination of Judge Sandile Ngcobo as Chief Justice, and has urged him to reconsider the matter.

DA leader Helen Zille said any comment would be "redundant" because Zuma has repeatedly indicated that the opposition's input, which he wanted by Monday, would not change his decision.

She said this became clear when he said on August 6 that he had "appointed a judge that I believe is capable".

It suggests, Zille added, that "his mind was closed on the matter, even prior to consulting".

She also cited a statement by Zuma's spokesperson Vincent Magwenya that the Presidency "cannot withdraw" the nomination.

"If eliciting advice is designed to inform one's decision, then that advice must be able to shape the outcome. If the President was unwilling, as a default position, to change his preferred candidate, any advice rendered is redundant," Zille said.

"Clearly, the Presidency believed the decision had already been made and the outcome decided."

Zille reiterated that Zuma asked the DA to comment on the nomination after it was made, prompting the DA, the Independent Democrats and the Congress of the People to write him a joint letter.

The parties asked that the President withdraw his statement that he had "appointed" Ngcobo as Chief Justice and that the process be reconstituted.

To date, Zuma has not responded directly to the letter, she said.

"The DA will await the President's response to our letter. If it is not forthcoming, we will consider our position and the options available to us, in taking this matter forward," she added.

She said the President had flaunted the Constitution, which requires proper consultation, and thereby opened the door to abuse of power.

"The consequence of this is profound. If the President does not consult properly ...then the practical effect is that the Chief Justice is appointed solely at the discretion of the President.

"That situation lends itself to the abuse of power, undermines the constitutional principle that there be a separation of power between the executive and judiciary and, in practical terms, runs the risk that the Chief Justice, and those candidates eligible for the position of Chief Justice might act in a manner designed to find favour with the President."