Papua New Guinea's Supreme Court has ruled that the head of the police fraud squad cannot participate in a National Court proceeding regarding the validity of an arrest warrant for the Prime minister.
Fraud squad detectives have sought the arrest of Peter O'Neill since 2014 for questioning over his role in alleged illegal state payments to a law firm.
After Peter O'Neill had launched a legal challenge on the validity of the arrest warrant, the national court had allowed fraud squad head Mathew Damaru and his fellow fraud squad officer Timothy Gitua to join the proceeding.
They had applied to join as they were directly involved in seeking the warrant of arrest for Mr O'Neill.
However a three-man Supreme Court bench has now ruled that a National Court judge made an error in allowing the fraud squad officers to join the proceeding.
The bench said the police commissioner Gary Baki was instead the appropriate person to represent the police force in the proceeding.
Mr Baki earlier attempted to sideline the fraud squad's attempts to arrest the prime minister.
Mr Damaru had argued that representation by Mr Baki was unsuitable because the commissioner opposed the warrant executed.
The Supreme Court bench however disagreed with him, saying members of the police force are obliged to follow directives from the Commissioner, who in this case was the fifth respondent.
The court has set aside the National court judgement and ordered for Mr Damaru and Mr Gitua to pay legal costs of the Prime Minister in this case.