Uncle Sam is taking sides in a battle between director Steven Spielberg and tech company Netflix over whether streaming movies that largely bypass theaters should be barred from winning an Oscar.

The US Department of Justice has sent a letter to the Academy of Motion Picture Arts and Sciences, the organization behind the Oscars, warning it about blocking streaming companies like Netflix and Amazon from competing for Oscar awards.

The letter, sent by the head of the Justice Department’s antitrust division to Academy CEO Dawn Hudson on March 21, comes as the Academy reportedly was getting ready to consider new rules — proposed by Spielberg — to restrict movies from competing for an Oscar unless they spent significant time on the big screen, and not just the small screen.

The proposed rule changes seem aimed directly at Netflix, which under CEO Reed Hastings scored three Academy Award wins this year for “Roma,” despite its limited theatrical run.

“Once you commit to a television format, you’re a TV movie,” Spielberg, an Academy governor, said in an interview with ITV News last year. “You certainly, if it’s a good show, deserve an Emmy — but not an Oscar. I don’t believe films that are just given token qualifications in a couple of theaters for less than a week should qualify for the Academy Award nomination.”

More recently, a spokesperson for Spielberg’s production company, Amblin, hinted that the director was planning to ensure that “Roma,” which was nominated for 10 Oscars, proved an outlier.

“Steven feels strongly about the difference between the streaming and theatrical situation,” the Amblin spokesperson told film blog IndieWire. “He’ll be happy if the others will join [his campaign] when that comes up [at the Academy Board of Governors meeting]. He will see what happens.”

According to the Justice Department’s antitrust chief, Makan Delrahim, forcing long theatrical runs could unfairly “suppress competition.”

“In the event that the Academy — an association that includes multiple competitors in its membership — establishes certain eligibility requirements for the Oscars that eliminate competition without procompetitive justification, such conduct may raise antitrust concerns,” said the letter, obtained by Variety.

The letter, which specifically referenced “films distributed via online streaming services,” was meant as a nudge, said a source who confirmed the exchange for The Post. If the Academy proceeds with the proposed changes, the Justice Department could kick off a probe into its practices, this person said.

Netflix, which has blasted Spielberg’s views about streaming movies on Twitter, did not ask the Justice Department to intervene, a person close to the company said.

The Academy confirmed receipt of the Justice Department’s letter Tuesday and said it “responded accordingly.”

A rep added: “The Academy’s Board of Governors will meet on April 23 for its annual awards rules meeting, where all branches submit possible updates for consideration.”