Mayor Bill de Blasio struggled Friday to bat away quid-pro-quo allegations reported by The Post over City Hall’s pro-Hotel Trades Council policy reversal — which came as the politically powerful union gave his quixotic presidential bid key support.

“That’s ridiculous,” a clearly peeved de Blasio claimed. “We’ve been working on this policy for years, have been implementing it around the city because hotels have a different impact on communities than other types of usage.”

He added: “That’s an outrageous allegation. In fact, we make decisions based on the merits.”

But good government activists offer a different interpretation of the events, saying they amount to another example of pay-to-play from the de Blasio administration.

City Hall ordered the Department of City Planning to study requiring that any new hotel be permitted by the City Council before it could open, overriding years of opposition from the planning agency and top de Blasio administration officials — including former Deputy Mayor Alicia Glen.

Currently, only hotels opened in recently rezoned neighborhoods like Midtown East or in manufacturing areas need Council approval.

The new policy would give HTC tremendous sway over opening new hotels in the city, effectively ensuring their staffs would be unionized.

City Planning officials confirmed that the administration requested the study based on conversations that began around April, just a month before de Blasio launched his flailing presidential campaign.

It was a stunning turn of events. Lawyers for HTC noted the ongoing opposition to the union’s permit plan dreams as recently as December 2018, a memorandum obtained by Politico New York shows.

The about-face came as de Blasio prepped and then launched his national campaign, which has leaned heavily on the HTC as it struggles to raise cash and meet the qualifying criteria for Democratic Party’s primary debates.

Its 40,000 members accounted for nearly 70% of Hizzoner’s 6,700 individual donations, an analysis by The Post and the Center for Public Integrity showed.

The about-face on permitting is the latest campaign finance and influence-peddling scandal to hit de Blasio as he has struggled to bolster his national political ambitions.

Hizzoner also faces two separate complaints with the Federal Elections Commission over using two different political accounts he controls — one state-based, the other federal — to circumvent contribution limits to his presidential campaign.

And de Blasio narrowly avoided indictment in an influence-peddling scandal in 2017 that was tied to his fundraising for a nonprofit controlled by his allies, the Campaign for One New York.

“He keeps taking the wrong lessons from these reprimands — that he can get away with things, rather than stop doing them,” Susan Lerner, the longtime head of the New York chapter of the left-leaning good government group Common Cause, told The Post in August as the news of the HTC hotel permit shift broke.

“It’s deeply upsetting and completely objectionable.”