SENATE President Stephen Parry has become the eighth MP embroiled in the citizenship scandal.
The Australian reports Tasmanian Senator Parry informed the government he believes he is a British citizen and may need to resign his position.
As Senate President, Senator Parry holds one of the most senior parliamentary positions.
The Australian confirmed Senator Parry sought formal advice from British authorities yesterday on whether he was a dual citizen in the wake of the High Court's bombshell decision that ruled Barnaby Joyce and four other MPs ineligible to sit in Parliament.
The landmark High Court ruling was a major blow to Malcolm Turnbull, who lost his one-seat majority in Parliament.
Only former Independent senator Nick Xenophon and Nationals senator Matt Canavan kept their seats after the High Court handed down its ruling on the "citizenship seven" - now to become "citizenship eight".
Deputy Prime Minister Barnaby Joyce will fight to regain the seat of New England with a by-election called for December 2.