Chief justice Mogoeng Mogoeng used an interview with the SABC on Tuesday to lambaste public representatives for not taking their oaths of office seriously.

"I am not about to play into the hands of those who want the judiciary to play second fiddle to the other arms of the state."

These were the words of chief justice Mogoeng Mogoeng in an interview with the SABC on Tuesday.

Mogoeng used the interview to lambaste public representatives for not taking their oaths of office seriously and weighed in on discussions around the trimming of the size of the cabinet.

The interview, which was streamed online, saw Mogoeng hit back at weekend reports that his office had spent R114m on travel and that he flew in first and business class. The report by GroundUp raised questions about the management of the office of the chief justice.

Mogoeng said he would not accept efforts to underplay the work of the judiciary. "Must I travel economy when my equals in other arms of the state are travelling business class or first class?" he asked.

"The executive even have jets to travel with. I am not asking for any jet. Why is it acceptable that others travel in groups of 25 or even 50 and I am not able to take four colleagues on any given time unless the trip is sponsored?"

In a wide-ranging interview, Mogoeng did not reject the possibility that he could run for political office once he retires as chief justice.

"If at any stage in my life people think there is any role I can play for the good of the South African public, I will reflect on it. Where I think I can make a difference, I will readily accept that responsibility," he said.

While Mogoeng said the judiciary was on high alert to not encroach on the functions of other arms of the state, as tempting as it may be, he weighed in on discussions that President Cyril Ramaphosa should drastically reduce the size of the executive.

"The possibility looms large to reduce cabinet and still be effective. I think there are a number of departments you can comfortably merge into one and still be effective," he said.

Mogoeng said he hoped there would be a "radical paradigm shift" in the incoming sixth administration.

Weighing in on the looming appointment of the cabinet, he advised: "Never appoint anyone to a position of responsibility who does not have the capacity to do the job ... If you are not satisfied that this person has the ability to meet responsibility, never appoint them. In that way, we will be able to achieve a lot much faster."

He will lead the swearing-in of MPs on Wednesday that will usher in the sixth parliament of South Africa's democracy.

Mogoeng said it was important for MPs to reflect on the oath and what it means to ordinary South Africans.

He said he believed the oath that is sworn or affirmed should be sent to MPs beforehand so they can familiarise themselves with what it entails - "otherwise it gets reduced to some kind of a song that you must sing before you assume your responsibilities".