An auction of Michael Jackson’s artworks has been hit with a “buyer beware” warning: the King of Pop’s estate claims there is no evidence he actually created the items.

Seventy-six pieces said to have been drawn or painted by Jackson, including watercolours and pencil sketches of subjects ranging from Queen Elizabeth II to US presidents, will be put on the block by King’s Auctions in California on Saturday.

The auction house is listing the collection for $1 million. If a buyer does not come forward, the works will be sold individually, with starting prices from $10,000 an item.

The sale has been complicated by a legal wrangle over the art and an announcement by the Michael Jackson estate that it does not believe they are