ST. PAUL — A Web site where people can register to vote in Minnesota is undergoing scrutiny in court.

A Ramsey County District judge was hearing a lawsuit Friday on the online sign-up tool launched in September by Secretary of State Mark Ritchie. A pair of conservative groups and a handful of Republican lawmakers have sued over its creation.

They want a judge to rule that Secretary of State Mark Ritchie exceeded his power by allowing online registration without explicit direction from the Legislature. Ritchie contends he had authority from other laws to set it up. His lawyers argue that the plaintiffs weren’t harmed by the site and shouldn’t be allowed to sue over it.

Thousands of voters who have already used the portal for registration could be affected by an eventual ruling.