An unnamed Middle Eastern buyer working with two local families has jumped into a high-stakes bidding fray by making an unsolicited offer of $2.1 billion for the Empire State Building.

This tops another unsolicited $2 billion offer for the world’s most famous skyscraper made by Woolworth Building part-owner, Rubin Schron, which was made public last week.

The Empire State Building is in the process of rolling into a multi-office building IPO by Malkin Holdings, which expects its partner in the operating company, the Helmsley Estate, to sell its shares to the public. There also are nearly 3,000 shares held by them and other small investors in the land under the building.

The Post has learned that Joe Tabak, of Princeton Holdings, and Philip Pilevsky, of Philips International, along with Pilevsky’s sons Michael and Seth, are working with the new Middle Eastern bidder.

“To this guy, it’s like buying a painting,” said a source of the Middle Easterner. “It will be very hard to stop them. They will keep ratcheting up [the offer] until they get it.”

While the buyer’s identity is not known, he is believed to be non-Arab.

Tabak sold the Ring portfolio, a group of Midtown South buildings, to Extell earlier this month. He also was an investor in one of the Toy buildings that was purchased from the Malkins. Pilevsky owns many properties in the tri-state area including 40 Rector St.

“This is a real bid,” said one source familiar with the thinking. “They will work with the Malkins and want to upscale the retail and make other changes.”

The 102-story building with 2.95 million square feet was valued at $2.3 billion in a filing with the Securities and Exchange Commission or roughly $780 per foot. By contrast, the city just valued the 88 percent-occupied property at $775,009,000. Even with some tax exemptions for its energy-efficiency and elevator improvements, it still pays roughly $31 million a year in property taxes.

In an June 24th SEC filing, the Malkins said, “We received last week two unsolicited bids to purchase the Empire State Building, one for $2 billion and one for $2.1 billion.

“We are reviewing the offers and their terms. We consider all matters, including unsolicited offers, consistent with our fiduciary duties, to form a judgment on what action is appropriate. We do not intend to issue a comment until after our review.”

The ESB’s ownership is divided into an operating partnership that includes the Malkins, son Anthony and father Peter, and the Helmsley interests. Along with small investors, they also own the ground under the building that receives rent for the “leasing” of the building.

Those small investors who have not voted in favor of the “consolidation” into an IPO were sent a 10-day notice to sell their shares in both the Empire State Building and another property at 60 E. 42nd St. for $100 a piece, since the supermajority of the investors voted yes on the IPO plan. The 2,884 shares in the ESB could be worth $320,000 each, an SEC filing previously said.

It is unclear what tax implications would mean for these investors if the building was sold outright, and it is unclear who else will jump into the bidding fray as news of the offers proliferates.

As for the rival Schron bid, Jason Meister, the investment broker from Avison Young who is representing him, said, “Our bid wasn’t out of left field as it is the most iconic building in the world.

“It is important to consider that our offer is for all cash with a $50 million nonrefundable deposit and may very well exceed what the REIT stock … ends up trading for. Our bid also allows for the investors to remain in the deal which is critical when considering the other bids. We await a response from Mr. Malkin.”

Lawyer Stephen Meister, who represents some of the smaller investors, said he is appealing a state court ruling that permitted the $100 per-share buyback. “If I win, the votes are void,” he said.

Meister also noted, “If the offer [for the Empire State Building] is a better one, he has a responsibility to consider it.”

No one returned calls for comment.