The High Court will determine if changes to the way Australians elect senators are constitutionally valid.
The court on Friday agreed to hear on May 2 a challenge to the laws, which make it more difficult for micro-party candidates to be elected, by Family First senator Bob Day.
The case runs alongside a class action mounted by the Three Million Voices committee.
Senator Day said the decision to hear the case proved there was merit in his case.
“Today was a really important win in the battle for voters’ rights and let’s be clear what happened last month in the parliament – voters’ rights were taken away,” he told reporters outside the court in Canberra.
The senator believes Australians who want to be represented by a micro-party are disadvantaged because their votes would exhaust under new ballot paper procedures.
The changes, which passed the parliament in March after marathon debate in the Senate, mean voters will be able to allocate their own preferences above the line.
If they choose to vote below the line, they will only have to number 12 boxes not every single box – which can be more than 100.
Senator Day and other crossbenchers are upset the rules also abolish group voting tickets, which help micro-party candidates win upper house seats with a very small primary vote.
The senator said his challenge had the support of his crossbench colleagues.
“Naturally, they believe that they were lawfully and legitimately elected,” he said.
The class action involves representatives from every state and territory, who argue Australians have been robbed of democracy.
“For the sake of Australian democracy, we cannot stand by and let this law stand that will cement the Greens into control for years to come,” committee coordinator Peter Madden said.
The hearing will run for two days.