The High Court has ruled Scott Ludlam, Larissa Waters, Fiona Nash, Barnaby Joyce and Malcolm Roberts ineligible to have stood for parliament at the 2016 election.
The question will now be whether Section 44 of the Constitution needs reform to enable dual citizens who may have a lot to offer to become MPs.
The High Court declared Barnaby Joyce ineligible to sit in parliament.
The High Court was unanimous on its decision in all the cases, with the eligibility of five MPs rejected and two upheld.
All eyes will be on the High Court as it decides the dual citizenship cases of (from left), Malcolm Roberts, Scott Ludlam, Larissa Waters, Barnaby Joyce, Fiona Nash, Matt Canavan and Nick Xenophon.
For Malcolm Turnbull, on a wafer-thin majority and struggling in the polls, the outcome of the seven High Court cases is of vital importance.
Malcolm Roberts is one of several MPs currently before the High Court.
The High Court has set hearing dates of October 10, 11 and 12 for MPs' dual citizenship cases.
The government tells High Court it would be willing to pay costs of those before the court
The government has asked the High Court to hear the dual citizenship cases of several current and former MPs on September 13-14.
Deputy Prime Minister Barnaby Joyce is one of five MPs caught out in the ban in dual citizens holding seats.
The High Court ruling over the five MPs' legitimacy to hold seats may hang on whether they took reasonable steps to renounce their non-Australian citizenships.
Matt Canavan has been told that he is an Italian citizen.
At the heart of the current controversy is that the senators were either ignorant of their second nationality or believed themselves to have lost it.
Matt Canavan told a news conference he had been informed he is an Italian citizen.
Matt Canavan has resigned as the minister for resources and northern Australia after being told by the Italian embassy that he is an Italian citizen.
The Greens have lost their two co-deputy leaders, Scott Ludlam and Larissa Waters, in a matter of days.
Given the events of the past week, now is an opportune time to discuss reform of a section of the Constitution that makes dual nationals ineligible to sit in parliament.
Larissa Waters is the second Greens senator to resign in less than a week.
Greens senator Larissa Waters was forced to resign on Tuesday after she discovered she was still a citizen of Canada.
The Australian system allows for fuel excise exemptions for off-road usage by the mining industry and by primary producers.
AAP Image/Alan Porritt
Critics of Australia's fuel tax credits system have pointed to its impact on the budget bottom line, but calculating that cost is far from straightforward.
The new leadership team: co-deputies Larissa Waters and Scott Ludlam flank leader Richard Di Natale.
The Greens mostly like to keep their party 'internals' internal. The leadership transition from Christine Milne to Victorian senator Richard Di Natale was marked by secrecy and tightly stitched up.
Where toys promote aggressiveness in boys and submissiveness in girls, they are definitely part of the problem.
Australia suffers “endemic” levels of men’s violence against women, so if the child is the father of the man, then it’s time we talked about boys’ toys. And what better time to start the conversation than…