Australian politicians will have to prove they are not foreign citizens under plans proposed on Monday as the conservative government grapples with a constitutional crisis that has cost it a majority in parliament.
Prime Minister Malcolm Turnbull announced a set of measures making it compulsory for MPs formally to declare they are not dual citizens and provide evidence to support it.
"Every member of the (lower) house and every member of the (upper house) Senate has a personal obligation to ensure that they are in compliance with the constitution," Turnbull said.
"If they have reason to believe that they are not, then they should say so and take the appropriate action."
The proposal, which requires cross-party agreement, comes amid a crisis that has seen several politicians fall foul of a previously obscure constitutional rule which bars dual citizens from sitting in parliament.
The Labor opposition has indicated it is open to discussing the new rules.
If they are ratified, each member of the upper and lower house will have 21 days to declare where they and their parents were born.
If they were formerly citizens of another country they must provide evidence that they have renounced it.
"Members and senators have been put squarely on notice now and so they will be turning their mind to their own affairs and the issues of citizenship, foreign citizenship," Turnbull added.
Australia's High Court last week ruled that five of seven politicians were in breach of the constitution even though they claimed to be unaware they held dual citizenship.
Four were born in Australia, while one moved from Canada when she was a baby.
Deputy Prime Minister Barnaby Joyce, who recently discovered he automatically acquired New Zealand citizenship through his father, was found ineligible to be in parliament.
His disqualification means a by-election for his lower house seat will be contested on December 2, upending the government's one-seat parliamentary majority.
The remaining four politicians, from various parties, sit in the Senate and are succeeded by MPs next in line from their own party.
The two who survived the High Court decision did so because their foreign citizenship status was inconclusive.
The dual citizenship rule was inserted into the 1901 constitution to ensure parliamentarians were loyal solely to Australia.
However, critics say it is out of step with the modern reality of the country, where 50% of the population are either foreign-born or the children of immigrants.