Backers of Arizona's sweeping new universal school voucher law are set to face off in court with opponents who collected enough signatures to block it until the November 2018 election.

Voucher supporters argue that problems with the referendum asking voters to overturn the law mean it should be thrown out and the law allowed to take effect.

Lawyers representing the grassroots group that collected signatures over the summer say voucher supporters have no right to sue. They will ask a judge Friday to dismiss the lawsuit.

Supporters raise several issues, including that petition sheets used to collect more than 110,000 signatures improperly identified the legislative session. They also say many were improperly notarized and raise a series of issues with signature-gatherers.

If the suit proceeds, other issues will be settled later.

The Associated Press contributed to this report.