Amanah supreme council member Mohamed Hanipa Maidin has urged Chief Justice Md Raus Sharif to tender his resignation.
The Sepang MP said he should do this before he is fired or made to face a tribunal.
“As we know, his appointment was full of controversy involving the Federal Constitution – our highest law of the land.
“In my view, he is only fit to be the chief justice for the BN era, not the Pakatan Harapan era,” he added.
Mohamed Hanipa said Harapan would reform the judiciary and does not see how the present chief justice would be able to serve in such an environment.
Previously, Amanah, Prime Minister Dr Mahathir Mohamad, and the Malaysian Bar had filed separate challenges against the appointment of Raus and Court of Appeal president Justice Zulkefli Ahmad Makinudin, who had exceeded the 66 years and six months compulsory retirement age.
Raus was scheduled for mandatory retirement, according to Article 125 (1) of the Federal Constitution, on Aug 4, last year.
However, he was on that day appointed as an additional judge before the Yang di-Pertuan Agong Sultan Muhammad V, on the advice of the previous chief justice, and was made chief justice thereafter.
The challenges were made on the grounds that Raus' appointment as an additional judge and his appointment as chief justice under Article 124 (4) of the Federal Constitution was unconstitutional, and thus invalid.
Malaysiakini is contacting Raus for comment.
Soon after winning the 14th general election, Mahathir had said that heads would roll in certain agencies and bodies.
His chief target was attorney-general Mohamed Apandi Ali, whom he accused of concealing evidence on the 1MDB scandal.
Mahathir also said there is no AG at the moment, but Apandi had clocked in for work, as usual, this morning.
Apandi had denied the allegation of being complicit in a cover-up of the 1MDB scandal.
This morning, MACC chief commissioner Dzulkifli Ahmad tendered his resignation after Mahathir accused the commission of ignoring widespread corruption and indicated a reshuffle.