TRENTON  The battle over a bill that would legalize gay marriage in New Jersey shifted locations unexpectedly late Wednesday as sponsors of the legislation canceled a vote scheduled for Thursday in the State Senate, where the measure appeared headed for defeat.

The sponsors, Senators Raymond J. Lesniak and Loretta Weinberg, both Democrats, withdrew the bill from the agenda in the Senate session, saying they wanted to first allow a hearing in the General Assembly, where support for same-sex marriage is believed to be stronger.

But opponents were outraged by the last-minute switch and accused Democrats of abusing their leadership positions to force a controversial issue through the Legislature during the waning days of the session. The bill was passed narrowly on Monday by a Senate committee.

“It makes a mockery of the legislative process,” said John Tomicki, president of the New Jersey Coalition to Preserve and Protect Marriage. “They’re using the Legislature as a propaganda tool. They didn’t have the courage to bring the issue up before the election, and now they’re playing games to do things that the public doesn’t approve of at the very last minute.”