TRENTON -- The group lobbying voters to approve expanding casino gambling to north Jersey announced Thursday it has suddenly suspended its advertising campaign -- the latest sign the high-profile referendum may be headed for failure.

The move by Our Turn NJ comes 47 days before New Jersey voters will decide a ballot question Nov. 8 asking them whether to allow two casinos to be built in the northern part of the state. If the effort passes, it would mark the first time gambling halls would be permitted outside of Atlantic City since they debuted there in 1978.

Paul Fireman and Jeff Gural, the businessmen who launched the group, said Thursday they "believe deeply" that expansion is a "remarkable opportunity that should not be squandered."

Fireman, the former Reebok CEO, has proposed building a casino in Jersey City, and Gural has proposed another at his Meadowlands Racetrack in East Rutherford.

"The data, however, speaks for itself," the developers said in a statement. "The current political climate in New Jersey and voters' concerns about the lack of details relating to the effort have proved overwhelming."

Proponents of northern gaming say it will bring millions in new revenue, thousands of new jobs, and provide tax money to help revitalize Atlantic City.

But recent polls have shown voters aren't behind the idea. State lawmakers have yet to establish where the casinos will be built and how much they would pay in taxes.

And an opposition group called Trenton's Bad Bet has flooded the airwaves and mailboxes with an ad blitz arguing that taxpayers can't trust state politicians on the matter.

Gural told the Associated Press he was blindsided by the message from the group, which is partly funded in part by Genting Group, the Malaysian company that operates the Resorts World casino at the Aqueduct Racetrack in New York City, which could be hurt by north Jersey casinos.

"I knew there was going to be a lot of money against us, but I didn't realize they would make it all about Trenton and not about casinos," he told the wire service.

Bill Cortese, executive director of Trenton's Bad Bet, told NJ Advance Media that his group has booked an additional $1.9 million in advertising through Oct. 3.

Cortese said the group will not be "distracted by billionaire developers throwing temper tantrums because they don't get what they want."

Our Turn NJ cited internal polling data that shows only 19 percent of voters believe the state is headed in the right direction and just 10 percent believe the state will deliver on the promised revenue.

The group also cites a Rutgers-Eagleton poll released this week that shows 58 percent of voters disapprove of the referendum, while 35 percent approve.

State Assemblyman Ralph Caputo (D-Essex), one of the key lawmakers pushing for the expansion, lamented the news Thursday. He said that if the referendum fails, casinos "just beyond New Jersey's borders will continue to get richer and richer thanks to patrons from New Jersey and elsewhere that previously traveled to Atlantic City."

Proponents would also have to wait at least two years before putting the question on the ballot again.

Jim Kirkos, president of the Meadowlands Regional Chamber of Commerce, said his group is "extremely disturbed to hear the news" of Our Turn NJ's decision.

"While we recognize that the polling numbers were an uphill climb and in this toxic climate left a difficult path to success, we do not think the voters ever had a clear understanding of the positive impacts New Jersey stands to gain if the referendum passes," Kirkos said.

State Senate President Stephen Sweeney (D-Gloucester), a co-sponsor of the expansion, did not immediately return a message seeking comment.

NJ Advance Media staff writer Jonathan D. Salant and the Associated Press contributed to this report.

Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01. Find NJ.com Politics on Facebook.