Najib filed the lawsuit in 2021, claiming that criminal charges filed against him during Thomas’ tenure were “part of a long-planned, premeditated exercise”.

However, the High Court struck out the lawsuit last year on grounds that the then attorney-general had immunity from being sued and that, in any event, his actions were non-justiciable.

Najib’s appeal is scheduled for hearing on Tuesday.

Lawyer Firoz Hussein Ahmad Jamaluddin told the court that Najib’s presence at the hearing is essential as the legal team would need to seek his instructions.

Justice Kamaludin Said, who chaired a three-man panel hearing the application, announced the court’s unanimous decision allowing the application.

Justices Lim Chong Fong and Azizul Azmi Adnan also sat on the panel.

Najib is serving a 12-year jail sentence at Kajang prison following his conviction for corruption and abuse of power in the SRC International case.

His suit alleges that Thomas had in 2012 formed an opinion against him in relation to 1MDB.

“After the general election in May 2018, he (Thomas) had made up his mind to charge the plaintiff (Najib) before studying the cases,” he said.

In Thomas’ bid to strike out the claim, he said that Najib’s lawsuit was filed for “political reasons”.