Khairuddin Abu Hassan, a stalwart of former prime minister Dr Mahathir Mohamad, has quit Parti Pribumi Bersatu Malaysia (Bersatu).

Khairuddin’s announcement, through a statement, came as a surprise as he had repeatedly said he would not join the party in the first place, and it was unclear when he actually joined Bersatu.

Khairuddin explained his departure is to allow him to focus on his series of legal challenges against Prime Minister Najib Abdul Razak.

“I need to focus all my time in a number of important trials to fight Najib’s (alleged) corruption and the abuse of our country’s institutions,” he said.

Najib had denied wrongdoing or taking public funds for personal gain.

Khairuddin's parting advice for Bersatu was that it should not become another Umno.

“Honestly and sincerely, all Bersatu leaders and members cannot engage in factionalism and must never allow Umno’s bad culture to seep into Bersatu,” he said.

He urged unity in the party and loyalty to the leadership.

However, Khairuddin indicated that he will still be speaking at Bersatu’s ceramah but will do so in his personal capacity.