The New Jersey Department of Transportation is reviewing whether a permit that it granted six years ago to a South Jersey company to build a controversial billboard on the Camden waterfront should be revoked.

The state launched the review last week on a request by Camden Lutheran Housing Inc., a vocal opponent of the billboard project that has divided the city. At issue is the zoning designation for the parcel at Elm Street and Delaware Avenue where the billboard would be erected and whether billboards are permitted under state and federal regulations.

Judy Drucker, a spokesperson for the Department of Transportation, confirmed that the state "is looking into the matter."

For the project — a 167-foot-high, two-sided billboard that would target the thousands of commuters who use the Ben Franklin Bridge every day  — to go forward, it needs approval from the state and the city.

By an 8-1 vote after a hotly debated meeting Monday night, the city Zoning Board approved a variance for the billboard. A variance was needed because the city's master plan prohibits billboards in the neighborhood.

Zoning Board Chairman Robert Hamilton, who supported the measure, called the opposition's objections "politics."

>>READ MORE: Camden mayor weighs veto

Camden Lutheran and other activists have raised questions about the permit issued in 2012 by the state to Interstate Outdoor Advertising for the project. Since then, the area's zoning has changed from industrial to a mixed waterfront designation, said Deena Greble, an attorney for Camden Lutheran, a nonprofit that has been working to transform North Camden.

"If you don't have a permit, you can't build," Greble said. "They need a state permit, no matter what the local Zoning Board decides."

In an email to Camden Lutheran last week, Elaine C. Schwartz, the Department of Transportation's manager for outdoor advertising, said the matter would be reviewed. A decision could come as early as next week.

"You have presented us with an issue regarding the current zoning at the permit location. As a result of this information, we are looking to see if the mixed waterfront zoning allows for billboards," Schwartz wrote. Her email was shared with the Zoning Board on Monday night.

Interstate Outdoor CEO Drew Katz on Friday dismissed the review.

"This is a non-issue," Katz wrote in an email. He said the state permit is "valid, and it's in order to erect a sign."

Katz said his firm has a lease to build on the site of an existing metal-finishing facility, which is an industrial use.

Mayor Frank Moran is weighing his option to veto the Zoning Board's decision. Moran did not respond Friday to a request seeking comment.

Opponents, who include the Cooper Grant Neighborhood Association and Concerned Citizens of North Camden, believe the billboard would change the architectural landscape of the waterfront, bring light pollution, and hamper economic development in the area. Supporters have rallied around plans by Katz to give the proceeds from the billboard to nonprofit groups in the city.

"We have never had a billionaire support the people in Camden," said former city councilman and activist Ali Sloan-El. "Why would you be against that?"

Under a proposal announced in April by Katz,  messages on two digital screens would target thousands of commuters who travel across the Ben Franklin Bridge. It would cost about $800,000 and take about six to eight months to build. Katz said the company was not ready to proceed with getting city approval after obtaining a state permit in 2012 because it didn't have the local support needed to get it approved.

The son of the late Lewis Katz, a Camden native who gave millions to his hometown, Drew Katz has said he came up with the billboard proposal as a way to carry on his father's philanthropic legacy. The elder Katz, a co-owner of the Inquirer and Daily News, died in a plane crash in May 2014.

Proceeds from advertising sales, about $200,000 annually, would be earmarked for nonprofits in the city. Grants would be distributed to charitable groups by a foundation.