Politics may make for strange bedfellows, but few are cozier than Mayor Bill de Blasio and the Big Apple’s hotel industry.

After getting a big boost during his first mayoral race from a cousin tied to the city’s hotel workers union, de Blasio has been buoyed by a flood of contributions from both labor and management that amounts to nearly 30% of the $2.3 million fueling his bid for the White House, records show.

A chunk of cash came from nearly 5,000 members of the New York Hotel Trades Council, which represents housekeepers, front-desk clerks and other workers and is the only labor organization to endorse de Blasio’s struggling presidential campaign.

The hotel employees — who gave a combined $89,000 — constitute 70% of de Blasio’s individual donors, according to his latest filing with the Federal Election Commission.

De Blasio and two political action committees he established also received about $300,000 from hotel owners and execs, records show, and two hotel industry PACs have paid for $256,000 in pro-de Blasio advertising, according to Issue One, a campaign finance reform group.

The favors flow both ways, with hotels benefitting from de Blasio’s battle against Airbnb and other services that offer tourists short-term apartment rentals in violation of state law.

De Blasio has boosted the annual budget for the city’s Office of Special Enforcement, which investigates civil quality-of-life complaints, by more than $6 million, leading to more than 4,000 inspections and 2,600 violations issued for illegal sublets during 2017.

“Generally, that’s seen as a positive for the hotel industry in that if people want to visit New York City they need to stay somewhere, and that is an alternative accommodation that is decreasing in terms of its availability based on the mayor’s crackdown,” said Sean Hennessy of the Lodging Advisors consulting firm.

City Hall is also fighting a federal suit that challenges a 2018 law requiring apartment-sharing “hosts” to register their homes with the Office of Special Enforcement.

The law has the potential to cut the number of Airbnb listings in the city in half, based on the results of a similar measure enacted in San Francisco.

De Blasio first got in bed with the hotel industry during his 2013 mayoral campaign, thanks to the help of John Wilhelm, a paternal first cousin and former president of UNITE HERE, the Hotel Trades Council’s parent union.

“It’s hard to overstate the role that Wilhelm played in de Blasio’s win. He picked up the phone and opened a lot of doors for Bill,” said a source close to de Blasio and the HTC.

The HTC endorsed then-Council Speaker Christine Quinn over de Blasio in the race, but her refusal to back a ban on Central Park carriage horses prompted UNITE HERE to donate $175,000 to an animal rights group that used the money to fund a barrage of negative ads against Quinn.

“Since the Mayor was Public Advocate, he has fought for thoughtful hotel development to maintain strong neighborhoods. To claim this is a newfound effort and not the continuation of years of dedication to this issue is revisionist history,” said mayoral spokeswoman Jane Meyer.

Additional reporting by Bruce Golding