A federal judge issued a temporary restraining order on Friday blocking a New Jersey law that would have allowed legal betting on sporting events.
U.S. District Judge Michael Shipp gave the order orally in court and planned to issue a written order later in the day, according to his chambers.
The National Football League and other sports leagues sued on Monday in an attempt to block the law that New Jersey Gov. Chris Christie, a Republican, signed a few days earlier.
A lawyer for the sports leagues confirmed the temporary order, but declined to comment further.
Christie spokesman Michael Drewniak said New Jersey plans to keep fighting the lawsuit.
"We continue to have full confidence in the strength and appropriateness of our position as we move forward in the litigation," he said in a statement.
The law would allow sports betting at state-licensed casinos and racetracks. The sports leagues said it violated a federal sports gambling ban and argued they would suffer irreparable harm if the law went into effect.
Monmouth Park, a thoroughbred race track in Oceanport, had planned to offer sports betting on Sunday.