The man who lost his seat after Tonga's Supreme Court ruled his 2014 election was invalid is appealing that decision.
Last month the Speaker of Parliament confirmed that Mateni Tapueluelu's Tongatapu seat was now vacant following the December court ruling.
The Attorney-General 'Aminiasi Kefu brought the case after he discovered Mr Tapueluelu had possibly breached electoral laws by failing to pay court fines.
The Constitution states MPs can only qualify if they have no outstanding fines.
In 2011, Mr Tapuelelu was fined just over US$6,500 after a defamation case brought by a former Minister of Justice over an article published in the Kele'a newspaper.
For three years, Mr Tapueluelu unsuccessfully legally appealed that case .
Radio Tonga reports his latest appeal is due to be heard in March.