The Solicitor-General in Tonga, Aminiasi Kefu, says the Crown expects a Court of Appeal decision this Friday over its challenge to the quashing of a perjury indictment brought against Lord Ramsay Dalgety.
He'd been secretary of the Shipping Corporation of Polynesia, the operator of the Princess Ashika, ferry which sank in August 2009 drowning 74 people.
After giving evidence at the commission of inquiry into the sinking, Lord Dalgety was charged with perjury.
Justice Robert Shuster quashed the charge on the grounds the indictment hadn't been signed, but Mr Kefu says the judge had no basis in Tongan law for such a decision.
"Essentially the Crown's contention was that His Honour had acted ultra vires or unlawfully because there was no law existing at that time when the indictment was filed, requiring the Crown to sign any indictments."
The shipping company, its chief executive and three others - the ship's captain and first mate and a government official - were last week convicted over their role in the ferry's sinking.