A New Jersey gambler who allegedly dumped his girl after they won $500,000 playing baccarat has upped the ante — threatening that he’ll release a sex tape if she doesn’t drop her lawsuit against him, she claims.

“It’s unbelievable,” says Jasmine Zheng, 21, of her alleged blackmailing ex-beau Zhiwei Zheng.

In happier days the couple made a mint at the tables in Atlantic City. Zhiwei, 26, posted pictures of himself with stacks of cash and casino chips on Facebook.

“Finally Made it!! 26 sittin’ on half a million!” he wrote in one since-deleted post. In another, he posted a photo of a “$38,000 Rolex … Mine for Life.”

Jasmine slapped Zhiwei with a Manhattan Federal Court lawsuit last week, claiming he stole her share of their winnings, bolted, and left her on the hook for the tax bill.

But after she ran to court, Zhiwei started dealing dirty, charges Jasmine.

“Zhiwei had his girlfriend threaten that if I don’t withdraw the lawsuit, they will do something against me,” Jasmine told The Post.

Zhiwei’s new girlfriend texted the threat to a mutual friend of Jasmine’s, writing in Chinese, “If they don’t withdraw the legal suit, then we will do according to our method,” followed by a 10-second video clip of a nude Jasmine and Zhiwei, Jasmine said.

The Manhattan woman claims she didn’t know her then-boyfriend was recording their intimate encounter last year.

“I thought he had deleted it,” she told The Post of the video.

She called the West New York, N.J., police department, where Zhiwei lives, but was referred instead to her local police, said Jasmine’s lawyer, James DeCristofaro.

“Stupid is bad enough by itself. But add reckless and it gets dangerous and it’s really stressing Jasmine out,” he said.

Zhiwei could not be reached.

The pair got lucky by pooling their money and playing baccarat during several trips to Atlantic City between December and February, Jasmine claims in court papers. They traveled back to

Zhiwei’s parents’ home above a Chinese restaurant in West New York, N.J., carrying their winnings in cash inside Zhiwei’s backpack.