President Trump needs to get behind plans for a new Hudson River rail tunnel and stop treating the project like a political poker chip, elected officials said Saturday.

Trump has asked GOP House leaders to cut $950 million in funding for the project, it was reported Friday — a move that drew the ire of local legislators on both sides of the aisle.

“This project is vital to 50 million people in the northeast corridor and to our American economy, and politics shouldn’t get in the way,” said Senate Democratic leader Chuck Schumer.

Rep. Peter King (R-LI) urged Trump to back the project.

“Trump must keep his commitment to Gateway which he made in White House last September,” King tweeted. “Essential to New York & Northeast.”

Trump’s aim in seeking to cut the project’s funding is unclear.

King suggested on Twitter that Trump is motivated by a dispute with Schumer, who has blocked some administration appointments. “Can’t let feud with Schumer hurt New York & United States,” King said.

If that’s the case, then Trump is acting “infantile” and “juvenile,” according to Rep. Jerrold Nadler (D-NY).

“What is this? Is this again part of his mean-spiritedness toward New York?” House Minority Leader Nancy Pelosi (D-Calif.) asked during an appearance in Queens on Saturday.

A source familiar with a meeting in September where Trump told local legislators he backs the new tunnel said the project isn’t sexy enough to interest him.

“He asked, ‘Why are we putting all this money toward a tunnel that no one can see?’ ” the source told The Post. “ ‘Why don’t we do something at LaGuardia’—because it’s visible.”

Trump is more interested in using the Gateway project as a bargaining chip, the source said. “This is throwing spaghetti at anything — anything to do deals.”

The $30 billion Gateway tunnel would supplement the existing century-old Hudson River tunnel. Planners say the new tunnel is a must for Amtrak and NJ Transit train service.

“This is not a partisan issue,” said Gov. Cuomo. “The President should . . . stop playing politics with our transportation network.”

In the Oval Office meeting in September, Schumer, Cuomo, and other officials argued that the federal government should pick up 50 percent of the tab for the project.

“Walking out of that meeting, I thought, if this were any other president, I’d be thinking he said yes,” Nadler told The Post.