The former Solicitor-General of Papua New Guinea wants his old job back and has gone to court to stop it from going to an Australian.
Zachary Gelu has asked PNG's National Court to stop the country's Attorney-General Francis Damen from advertising the position.
Mr Gelu is back in the public service after he was suspended as Solicitor-General in March.
Canberra and Port Moresby have agreed to the appointment of an Australian to the post as part of the Enhanced Co-Operation Programme.
The US$650 million deal has brought Australian police and public service officials to work in PNG.
Mr Gelu's application is expected to return to the National Court on Monday.
It is the second lawsuit launched against aspects of the Australian mission.
The MP Luther Wenge will appear in the National Court next week to contest key components of the ECP.
Mr Wenge says laws passed in PNG which shield Australians working in the programme from prosecution, breached the PNG constitution.