He follows three New Zealanders in the role.
When being briefed by members of the Tonga Police Senior Executive on the range of policing services undertaken by Tonga Police, the Commissioner was keen to understand the difficulties faced by officers across Tonga.
Commissioner McLennan was sworn in by the Chief Magistrate Folau Lokotui after arriving in the country on May 11.
RNZ Pacific reports the Commissioner has a broad policing career that spans over 40 years, having commenced with the Queensland Police Service as a police cadet at the tender age of 15.