Canberra: Five Australian parliamentarians were ousted on Wednesday for holding dual citizenship when they were elected. It comes as fresh blow to Prime Minister Malcom Turnbull's majority in the House.
In what was widely viewed as a fresh test case, a high court ruled Senator Katy Gallagher ineligible, the BBC reported. Four other politicians, who were also under scrutiny resigned after the verdict.
Gallagher and lower house MPs Justine Keay, Josh Wilson and Susan Lamb are members of the opposition Labor party. The fifth MP, Rebekha Sharkie, is part of minor party Centre Alliance.
In 2017, 10 MPs and senators were removed from office for violating a constitutional rule that prohibits federal political candidates from being dual nationals, the BBC report said.
The dual citizenship saga has destabilised Australian politics since July 2017, at times threatening Turnbull's majority in the House of Representatives. Turnbull could increase his majority if he wins any of the vacant lower house seats, the BBC reported.
Gallagher was aware of her British passport as her father was born in England, so the court ruled that she did not take "all reasonable steps" to relinquish her British links, Xinhua news agency reported.
The High Court of Australia ruled that Gallagher's seat would be filled by counting back votes from the 2016 federal election. The other politicians are expected be replaced in the same way, or through a by-election.
Gallagher had referred herself to the court in 2017 after questions emerged over whether she had renounced her British citizenship in time to run for office.
"To the people of the (Australian Capital Territory), I'm very sorry that this disruption has occurred to one of your federal representatives," she said on Wednesday.
Labor leader Bill Shorten said three of the ousted MPs would seek re-election.
Shorten said his party had relied on an older interpretation of Section 44(a), a much-debated rule in the constitution, that says members of parliament cannot continue to have citizenship in another country, and must prove they took "all reasonable steps" to renounce the other citizenship before being elected.