Prime Minister Dr Mahathir Mohamad must explain the appointment of former Attorney-General Mohtar Abdullah as Federal Court judge, as it has become the most controversial judicial appointment in the nation's history, asserts an opposition leader.

DAP chairman Lim Kit Siang called on Mahathir to explain whether Mohtar's appointment was to checkmate Chief Justice Mohamed Dzaiddin Abdullah's expressed "first priority", which is to restore public and international confidence in the judiciary.

"Mohtar's appointment has dampened public optimism about the success of Dzaiddin's judicial reforms," he said in a press statement.

Lim added that the prime minister should also reveal who he had consulted before the reference to the Conference of Rulers on Mohtar's appointment.

"Mohtar's appointment has highlighted the need for reform and modernisation of justice in Malaysia to introduce a transparent judicial appointment process as a precondition to the restoration of public confidence in the judiciary as is practised in other Commonwealth countries," he said.

The Malaysian people, he said, should be informed of the procedures followed in the appointments to higher courts, and that they involve a thorough process of consultation and enquiry with professional groups and people who can speak for public interest.

Mohtar, whose term of service as AG expired on Dec 31 last year, was appointed a Federal Court judge on Jan 23.

He was among several candidates tipped to succeed Eusoff Chin as the new Chief Justice. However, following the appointment of Dzaiddin as CJ, Mohtar was subsequently appointed as a Federal Court judge, which raised many eyebrows.

Before being appointed AG in 1994, Mohtar was a High Court judge serving in Kuala Lumpur and Ipoh. He is also the first AG to be appointed as a Federal Court judge.