ATLANTIC CITY - There may be more problems for the already struggling Atlantic City, as the main casino workers union takes to the airwaves to explain why its members are threatening to strike next week.

Local 54 of the Unite-HERE union will start an advertising campaign Thursday on radio stations in southern New Jersey and Philadelphia laying out why they are threatening to strike. 

The walkout would affect Bally's, Caesars, Harrah's, the Tropicana and the Trump Taj Mahal. Workers are expected to strike unless a contract is reached by July 1.

The union is trying to regain some of what it gave back to the casinos in past contracts now that the casinos' finances are stabilizing somewhat.

While declining to reveal the cost, the union calls it a "significant ad buy" that will run between Thursday and July 1.

The Associated Press wire services contributed to this report.