That is certainly the question now in Australia as four Senators have been forced to declare dual citizenship and thus ineligibility

Each circumstance is bizzairre such as arrival as infants, being nominated for citizenship by your parent as an adult or the latest revelation that he revoked his citizenship but it wasn't acknowledged until after the election

Senator Malcolm Roberts dual citizenship in question

The government has passed some radical changes with the help of these now deposed senators and the whole structure of the next legislative session hangs in the balance, but the more interesting is that these erstwhile citizens are members of minor parties, no one in the major parties has owned up yet

Ah, Constitutions, they are hard to get around but apparently not as hard as some think
Until the Parliament otherwise provides, the qualifications of a member of the House of Representatives shall be as follows:

  • he must be of the full age of twenty-one years, and must be an elector entitled to vote at the election of members of the House of Representatives, or a person qualified to become such elector, and must have been for three years at the least a resident within the limits of the Commonwealth as existing at the time when he is chosen;
  • he must be a subject of the Queen, either natural-born or for at least five years naturalized under a law of the United Kingdom, or of a Colony which has become or becomes a State, or of the Commonwealth, or of a State.

The qualifications of a Senator shall be the same as those of members of the House of Representatives
A change to qualifications can be decided by the parliament, not by plebicite as some think, and does this mean a citizen of the UK or NZ is eligible, a somewhat vague clause, but the matter has since been resolved by many changes to citizenship, meaning no citizen of another country can hold a seat in federal parliament unless they have made all reasonable efforts to renounce citizenship of another country.

How do you renounce a citizenship you didn't know you had, a true dilema