In a trial challenging the US state of Wisconsin’s same-sex marriage ban, a federal judge has dismissed three defendants.

District Judge Barbara Crabb dismissed district attorneys in two counties, saying the case should be limited to those public officials who actively block the plaintiff’s ability to marry.

The ACLU, which filed the lawsuit in February on behalf of eight couples, did not oppose the dismissal of the attorneys from Eau Claire and Milwaukee.

According to reports state revenue secretary Rick Chandler was also dismissed for similar reasons.

Remaining as defendants in the case are Governor Scott Walker and Attorney General JB Van Hollen.

The American Civil Liberties Union earlier this year asked District Judge Barbara Crabb to suspend the ban via a preliminary injunction as part of their challenge to the ban.

Since she declined their request warning that any injunction could quickly be overturned on procedural grounds.

In 2006, voters in Wisconsin approved a referendum banning same-sex marriage.