The New Zealand based Tongan Advisory Council says an inquiry into the sinking of the Princess Ashika should be allowed to proceed without interference.
The call comes after Tonga's public servants association launched a petition seeking the resignation of the Prime Minister, Dr Feleti Sevele.
The petition accuses the Prime Minister of being responsible for last month's sinking, in which 74 people died.
Melino Maka of the Advisory Council says the PSA's call is partisan political posturing and is not consistent with the role of a professional, independent public service.
The Royal Commission to investigate the sinking is yet to start its work and Mr Maka says it should have the opportunity to do its work without being prejudged.
He says given the important constitutional and political developments now being considered in Tonga, people holding responsible office need to show leadership.
