The Commission of Inquiry into State Capture may approach the Constitutional Court to get former president Jacob Zuma to answer questions in the forum, according to a letter his lawyer said he received.

Zuma is scheduled to appear before the commission between 16-20 November.

He appeared in July last year, and subsequent attempts at scheduling his return have been stymied by illness or a prior engagement.

Zuma's lawyer, Eric Mabuza, said he had received a letter from the commission as to whether Zuma would attend or not.

"They said if we don't [reply], they will go to the Constitutional Court," said Mabuza on Wednesday.

A summons for Zuma to return to the commission was issued in October, in terms of the commission's rules.

Mabuza said he did not know yet on what grounds the matter could be brought to the consideration of the judges of the Constitutional Court.

The latest development comes as former South African Airways board director Dudu Miyeni appeared via a video link on Wednesday.

She said she preferred not to answer questions on the grounds that she might incriminate herself.

Her replies on Wednesday were repetitions of that stock reply that she would not answer.

As the Deputy Chief Justice, the commission's chairperson, Raymond Zondo, is ordinarily based at the Constitutional Court.

He was appointed to preside over the commission by Chief Justice Mogoeng Mogoeng.

Zuma appointed the inquiry on the recommendation of former public protector Thuli Madonsela.

Ordinarily, he would also have chosen the presiding officer, but due to allegations implicating Zuma himself in alleged state capture, Madonsela felt it prudent to pass the task of choosing a presiding officer to the chief justice.

Zuma's attorney has already indicated that he might bring an application for the recusal of Zondo due to a family history between Zondo and Zuma.

Zondo recently broke his silence ahead of the possible recusal application to explain that he had a child with Zuma's sister-in-law about 25 years ago, long before Zuma married the child's aunt, Thobeka Madiba.

Zuma's presence at the inquiry was ordered for the purposes of giving evidence before the commission and being questioned on certain matters relating to the investigations of the commission.

Commission secretary Professor Itumeleng Mosala said he could not comment on correspondence.

Comment was requested from spokesperson, Reverend Mbuyiselo Stemela, and the replies will be added when received.