The High Court has ruled that parts of the Electoral Act are unconstitutional opening the way for an extra 100,000 people to vote on 21 August.
The majority High Court decision declared that provisions introduced by the Howard government, which removed the seven day close of rolls period, are invalid.
Under the new law, the roll closes the day the election writs are issued.
The case was brought by the independent political movement GetUp.
On it's web site GetUp thanked Rights Legal Resource Centre and thousands of GetUp members who contributed to the case.
Special Minister of State, Senator Joe Ludwig, welcomed the Court's ruling.
He said it acknowledged that thousands of potential voters should have had the opportunity to have their say on election day.
"Federal Labor welcomes any decision which restores the right of thousands of Australians, particularly young people, to vote in this election," Joe Ludwig said.
"We understand the AEC are ready to start processing the enrolment applications they received that missed the early cut-off," he said.
