Former Independent Police Investigative Directorate (IPID) boss Robert McBride in his evidence to the state capture inquiry is expected to testify about deputy chief justice Raymond Zondo's younger brother, Mxolisi.

A possible conflict of interest had to be dealt with by the commission's legal team before McBride could testify on Thursday.

Mxolisi Zondo chaired an inquiry into the controversial illegal deportation of five Zimbabweans in 2010, a matter that resulted in former Gauteng Hawks head Maj-Gen Shadrack Sibiya being axed.

McBride is expected to give his opinion on Mxolisi's 2015 findings.

Advocate Paul Pretorius, who leads the commission's legal team, said no parties, including McBride, objected to the deputy chief justice hearing the evidence.

"He [McBride] will testify to a range of matters and a range of disciplinary hearings, as well as inquiries. One of those inquiries was chaired by Mxolisi Zondo, the chairman’s younger brother. An issue then arises whether you as chair should hear that part of the evidence," Pretorius told Zondo. "There is no objection raised by any person directly involved in this evidence."

Mxolisi wrote to the commission and submitted the full record of his inquiry. He said he would not apply to cross-examine or give his own version at the commission.

"Considering the nature of the evidence, it is an opinion of the conduct of [Mxolisi] in a disciplinary inquiry where he chaired that inquiry. That record is available," said Pretorius.

"The nature of the evidence by McBride is an opinion. The proportion of that evidence is minuscule. It is not something that is essential to the points that he wishes to make."

The commission's legal team has recommended that Zondo hear McBride's evidence on his brother but not make any findings on it until later.