The gavel will come down next week on treasures fished out of a New Jersey storage locker — two paintings believed to be by famed artist Willem de Kooning and one by modernist master Paul Klee.

Gallery owner David Killen hopes his finds — part of a cache of 200 artworks he purchased on a hunch last year for $15,000 — will fetch millions.

The bidding, which began online Sept. 3 and started at $1,000 per painting, was up to $2,600 on one of the de Koonings by Saturday.

But it is expected to go much higher.

“The smart money waits to the last minute,” Killen said.

Killen, 59, who began shopping at flea markets as a child and now runs an eponymous Chelsea gallery, took a chance last year when he bought the contents of a Ho-Ho-Kus storage facility that came from the Manhattan studio of art restorer Orrin Riley, who died in 1986.

Riley’s girlfriend inherited the business, but she was killed while crossing the street in 2009. Her death left two friends to track down the paintings’ owners. What couldn’t be returned was considered abandoned property and the friends put it up for sale.

Killen was skeptical the collection contained anything valuable and was floored to see boxes marked “de Kooning” when he went to collect the goods.

Killen had Lawrence Castagna, an art-restoration expert based in East Hampton who worked both in Riley’s studio and as an assistant for de Kooning, examine the paintings.

Castagna told The Post he believed the paintings were the real thing.

The de Kooning Foundation does not authenticate the artist’s work. De Kooning, a Dutch-born master who died in 1997, is best known for his abstract paintings. His “Untitled XXV” fetched a staggering $66.3 million at a 2016 auction.

The work by Klee is among the artist’s known paintings but it has been marred by an ink stain which is likely why it was in Riley’s studio. It is part of the “curtain” series by the Swiss-born modernist, one of which is in the Guggenheim Museum. Before it was damaged, it was up for auction in London in 1990 and estimated to bring in up to $572,000, but did not sell.

After The Post reported news of Killen’s purchase in July, news outlets around the world picked up the story.

He has already sold some $50,000 worth of artwork from the locker, including a photo collage by the British duo Gilbert & George that went for $10,000. Buyers pay a 20 percent premium on top of the sale price.

The rest of the six de Koonings will be auctioned later this fall. Killen said he’s heard estimates from tens of thousands of dollars to millions.

He said his 82-year-old mother from Brooklyn was optimistic and would be in the front row during the auction at Killen’s 25th Street gallery “with a grin on her face.”

“I think she’s been waiting for this her whole life,” he said.