COLUMBIA -- A new federal regulation requiring businesses to tell workers they have a right to join unions and discuss working conditions is facing a new legal challenge from a national small business group.

The National Federation of Independent Business said Friday it sued the National Labor Relations Board in federal court in Washington over the regulation that goes into effect in November. Its challenge will join others, including one from the National Association of Manufacturers.

Karen Harned, executive director of the federation's small business legal center, said the NLRB doesn't have the authority to require the 11-inch by 17-inch posters or to tell employers what they need to say to their workers.

"They're telling us what to say in regard to unions in a way that we don't think is necessarily neutral as to whether or not you should join unions," Harned said.

Businesses that don't have the poster would be asked to put one up but the board can't fine employers who don't comply.

An NLRB spokesman said it is reviewing the litigation and had no comment on the legal challenge.

South Carolina's House this year passed legislation saying businesses don't have to comply. That bill is now in a Senate committee.

The poster lists in plain language long-standing federal law, including that employers can't keep workers from talking about working conditions on breaks or away from the job, that unions can't coerce workers to join and that employers have to bargain in good faith with workers covered by a contract. It tells workers that illegal conduct won't be permitted and how to contact the NLRB.