Page Six says Michael Jackson is trying to put the kibosh on an upcoming Vegas auction of Jackson and Jackson 5 memorbilia, saying he's the rightful owner of all the items, and he's set to argue his case at a closed-door hearing in Las Vegas tomorrow.

Last year, Richard Altomare, chairman of Florida-based Universal Express, bought more than 20,000 Jackson family artifacts from Henry Vacaro, a former business partner of Wacko Jacko who won the collection as part of a New Jersey bankruptcy case. They include all of Michael and his siblings' costumes from their Jackson 5 days through the '90s. Among the most coveted prizes are Jacko's trademark sunglasses and black fedora, a jacket with gold-sequined epaulets he wore in his "Moonwalking" days, Janet Jackson's ballet shoes and a Mae West costume she donned onstage, and handwritten Jackson 5 lyrics and never-before-released recordings.

That has Altomare fuming, particularly since he's withheld numerous items from the auction, slated for May 30-31 at the Hard Rock Hotel & Casino in Vegas, because of their "salacious" nature. "There are a couple of paintings Jackson made of children, of boys - naked," Altomare told Page Six. "And there are some of his whitening creams, some sex aids . . . some of the old records in his sealed [sexual molestation] court case.

"This is stuff we have kept from the auction out of respect to Mr. Jackson. The guy has troubles. We all have skeletons in the closet and, if Michael hadn't put up a fuss, I might have quietly, discreetly, just given it to him. I'm a Brooklyn kid and a gentleman . . . But if he p - - - - s me off, I may end up auctioning them."