Los Angeles, California (CNN) -- A spokesman for the trustees who control Michael Jackson's estate said designer belts produced under a contract with the pop icon's parents were not authorized.
Asked if there would be legal action to stop the marketing of the belts, estate spokesman Jim Bates said it was undecided.
Another company, Bravado, has a contract with the estate to market Michael Jackson merchandise, Bates said.
A representative of the company marketing the belt said Katherine Jackson, the late pop star's mother, cleared the deal with the trustees.
The sale has been put on hold while lawyers discuss a solution, he said.
The crystal-encrusted belts, which went on sale through the designer's website Wednesday, are intended to raise money for the Jackson family museum planned for Gary, Indiana, according to a family friend involved in the deal.
The first belt produced -- known as the "artist's proof" -- was autographed by Michael Jackson's three children and his parents for a special auction set to start Thursday.
Katherine Jackson and her grandchildren Prince, Paris and Blanket Jackson are the chief beneficiaries of the Michael Jackson estate. Charities yet to be chosen will also get 20 percent of the estate's profits, according to the will signed by Jackson.
Katherine Jackson dropped her challenge for control of her son's estate in October, but her husband still has a legal objection pending in probate court.
"This is a truly one-of-a-kind opportunity," said Jerry Olivarez, the Jackson family friend who helped bring the deal together. "I know of no other item that has ever been made available to the public that has been signed by both the parents and children of Michael Jackson."
Blanket, whose real name is Prince Michael II, Paris and Prince Jackson each signed the artist proof belt at the Encino, California, home where they live with their grandmother.
The youngest, who was born in 2002, signed his name in true "John Hancock" style, taking up the most room with large block letters spelling "BLANKET."
Prince, 13, helped his younger brother by adding "Jackson" below his first name.
Paris, 12, showed flair with her signature, using a heart to dot her "i" and giving her "r" a long, flowing branch.
The leather belt was designed by Simon Tavassoli and a limited run of 7,000 are being handmade at his Newport Beach, California, studio. Each unsigned belt will retail for $1,500, he said.