President Joe Biden has just a nine point over Donald Trump in a new poll of deep blue New York, a state he won by 23 points in 2020, according to a new Siena College survey.

Biden, 80, had enjoyed a 21 point lead over the Republican frontrunner in a September poll by the upstate college, however a new poll released Tuesday found the Democratic incumbent was only ahead by 46-37% in a head-to-head matchup against Trump, 77.

His lead further evaporated to seven points over Trump – who is accused of 91 felonies – when third party candidates Robert F Kennedy Jr. and Cornell West were added to the equation, the survey found.

Biden’s diminished lead is less than a third of his margin of victory in 2020, when he beat Trump by 61-38% in the Empire State.

Political strategist Hank Sheinkopf calling Biden’s diminished lead in a state where Democrats outnumber Republicans by more than two to one “shocking.”

“If Biden is in trouble in one of the bluest states, imagine what’s happening in the rest of the country,” Sheinkopf said.

“It’s a clear message to the Democrats. If it ain’t working in New York, don’t take the show on the road.”

The new poll found Biden’s popularity with his base has been weighed down by the migrant crisis at the southern border, which has led to more than 130,000 asylum seekers coming through New York City since last spring.

“Voters are angry. It’s the migrants, the economy. People don’t think Biden is strong enough to handle the challenges. This is not good news for Democrats in New York State,” Sheinkopf said.

“This is a wake-up alarm,” said former Staten Island and Brooklyn Rep. Max Rose, a Democrat.

“This is a wake-up bullhorn. The Biden administration and Democrats have to show they can effectively and humanely manage the migrant issue or face serious election consequences.”

Sixty-five percent of New Yorkers said the US was headed in the wrong direction under the president and 55% of state residents had an unfavorable view of Biden the poll said, about a percentage point more that his reported national disapproval rating.

“I knew Biden was the problem when I read he visited New York City and didn’t even acknowledge the migrant problem. How can you ignore a problem when it’s right in your face?,” said Robert, a 32-year-old tax preparer told The Post at Brooklyn’s Atlantic Terminal.

“He’s king of denial and I would rather not vote at all than vote him back in,” he continued.

The last GOP candidate to win New York’s electoral votes was Ronald Reagan in 1984. Republicans did manage to flip four House seats in the state last year as former Rep. Lee Zeldin ran a competitive race for governor against the incumbent Democrat, Gov. Kathy Hochul.

Siena College surveyed 1,225 registered voters in the state between October 15-19.