A new radio ad features Gov. Nikki Haley urging Boeing South Carolina workers not to join the International Association of Machinists union.

The spot is scheduled to start airing on stations in the Charleston region Monday, The Post and Courier has learned. The newspaper heard a copy of the new Boeing ad Sunday.

Haley has been an outspoken opponent of unions.

The IAM, which represents thousands of Boeing production workers in Washington state, has been ramping up efforts to organize the company’s North Charleston operations, where Boeing makes the 787 Dreamliner. The ad says union representatives have been knocking on workers’ doors at home.

Boeing South Carolina has been pushing back. It ran its first local radio ads over the holidays asking worker not to sign an IAM union card. More recently, the company set up a website — weareboeingsc.com — to make its case to its South Carolina employees. That website is mentioned in the new ad.

John McDermott