NEWPORT BEACH, CALIF. — The maker of Hydrox cookies has filed a complaint with the Federal Trade Commission alleging that Mondelez International, Inc., the maker of Oreo cookies, is involved in the hiding of Hydrox cookies at retail stores, according to an Aug. 6 post on the Hydrox Facebook page.

Competition between the two brands dates back more than 100 years. Newport Beach-based Leaf Brands relaunched the Hydrox brand in September 2015.

The Facebook post said people have sent in photos showing Hydrox cookie packages that were moved or blocked from store shelves, making it more difficult for shoppers to see the cookies. Several photographs appear in the Facebook post.

Mondelez International, East Hanover, N.J., runs a director-store-distribution system, which the Facebook post alleges gives Mondelez workers the opportunity to move around packages when they restock store shelves. A buyer for a retail chain told Leaf Brands that Mondelez workers were hiding Hydrox cookies, the post said. In contrast, supermarket employees restock Hydrox cookies from the supermarket warehouses.

The F.T.C. has asked for more information after receiving the initial complaint, and Leaf Brands is preparing to send additional information, said Ellia Kassoff, chief executive officer of Leaf Brands.

“We have not been contacted about this, but we are confident that this accusation has no merit,” a Mondelez spokesperson said. “The Oreo brand is an iconic one, with a proud and rich history of delivering great tasting products and exciting innovations to our consumers for more than a century. This focus, and our commitment to operating with integrity, has made Oreo America’s favorite cookie.”

Hydrox cookies, originally manufactured by Sunshine Biscuits, made their debut in 1908. Oreos, first made by the National Biscuit Co. (Nabisco), followed in 1912. Keebler purchased Sunshine Biscuits in 1996 and replaced Hydrox with a reformulated product called Droxies in 1999. Leaf Brands brought back the original Hydrox cookies 16 years later.

Oreo continues to lead the overall cookie category. Mondelez had U.S. retail sales of $3,306.5 million to lead all vendors in the cookie category for the 52 weeks ended July 15, 2018, according to Information Resources, Inc., a Chicago-based market research firm. Oreo, the No. 1 brand, had sales of $661.2 million. Oreo Double Stuf was No. 4 with sales of $260.8 million, and Oreo Thins was No. 6 with sales of $172 million.