Two more Turnbull government MPs could be tripped up by the High Court after it ruled a Liberal candidate was ineligible to take the Senate seat of former cabinet minister Fiona Nash.
Ms Nash was disqualified by the High Court on October 27 because she held dual citizenship, in breach of section 44 of the constitution.
Hollie Hughes was the next candidate on the NSW coalition Senate ticket at the 2016 election behind the then-Nationals deputy, and was due to take Ms Nash's seat following a court-ordered special count.
However, the court on Wednesday ruled Ms Hughes could not take up the seat because she was also disqualified.
Ms Hughes was appointed a part-time member of the Administrative Appeals Tribunal on July 1 this year, which the government admitted to the court was an "office of profit under the Crown".
The ruling has heightened concerns inside the government that assistant minister David Russell - who is facing his own High Court battle - and Nationals colleague Barry O'Sullivan might be disqualified for similar reasons.
Attorney-General George Brandis wouldn't be drawn into speculation about the pair's future until the court's reasoning in the Hughes case is made public.
"Let us see, let us see what the High Court says," he told Sky News on Thursday.
In the Hughes case, the government argued Ms Hughes did not hold the AAT position at any time between her nomination for election and the declaration of the election result in 2016.
However the court heard the fact she held the AAT position between September 4-5, when the Senate resolved to refer the Nash case to the court, and October 27, should render her ineligible.
The NSW Liberal Party is awaiting further direction from the court, but commended Ms Hughes for seeking clarification of her status.
It is expected if there is another special count the seat could go to Liberal candidate, Major General Jim Molan, a key ally of Tony Abbott.
Labor senator Penny Wong said it was a "humiliating defeat" for the government and showed it could not be trusted.
