WASHINGTON — Former aides to President Biden say they’re outraged that White House chief of staff Jeff Zients dismissed their allegations of bullying and verbal sexual harassment against first lady Jill Biden’s top aide Anthony Bernal — with Zients declaring them “unfounded attacks” without investigating.

Three sources exclusively told The Post that Bernal, who is considered one of the most powerful officials at the White House due to his relationship with the first lady, repeatedly speculated to them about the penis sizes of coworkers and inappropriately postulated the sexuality of peers.

Zients said in response to those complaints that he and the first couple “have full confidence in Anthony’s character” and that “[i]t is disappointing that he is the target of unfounded attacks from unnamed sources” — a statement that a prominent sexual harassment expert called “an incredible no-no.”

“What kind of message does that send to the staff who work for Jeff?” a former senior White House official asked Tuesday.

“If they didn’t know that they had zero recourse before the story, Jeff made it pretty clear that if you’re harassed by senior staff at the White House, his door is closed, and he doesn’t want to hear you,” the person added.

“That statement sent a huge smoke signal to the staff inside the building to just go to the press, not the chief of staff.”

The ex-official went on: “A White House chief of staff should not be placed in a position to condone abuse and harassment from his own personnel in any place, let alone the White House. The first thing Jeff should do is fire whomever convinced him to put his name on that statement.”

A second source said that Zients’ statement both “shows how powerful and untouchable Anthony is” and stunned peers who have worked for Biden.

“It’s outrageous that the chief of staff dismisses Anthony’s repeated abusive behavior as ‘unfounded attacks’ straight out of hand without investigating them,” this person said.

“It comes from the top. The Bidens are more interested in shielding a known predator than protecting [verbal] abuse victims.”

Zients and a spokesperson for the first lady’s office did not immediately offer a statement in response to the criticism.

Louise Fitzgerald, a professor emerita at the University of Illinois Urbana-Champaign who has consulted for federal agencies on sexual harassment and served as an expert in high-profile federal court cases, told The Post that Zients’ brush-off was a red flag.

“In a private corporation, that is an incredible no-no,” said Fitzgerald.

“I don’t know how it works if you are a federal employee, but in the private sector, not investigating would increase your liability, immensely.”

Zients is a successful businessman with a reported net worth of between $89 million and $442 million. He has held significant corporate management positions, including serving on Facebook’s board from 2018 to 2020 and as CEO of investment company Cranemere.

He is also an investor in the successful DC-area bagel chain Call Your Mother.

“You can’t tell me that Jeff Zients, a respected man in politics and business, a consummate professional, would ever allow any of his four children to be treated that way in the workplace,” said one of The Post’s sources.

“His statement reads like a script from a hostage video with a captive who had a gun to his head. Who would want their kid or sibling to go work for a guy like Jeff Zients now, after seeing those comments?”

Bernal’s alleged bullying behavior toward staffers, including making peers cry, spreading demeaning gossip, and hounding subordinates with capricious and overbearing demands, was previously reported in August 2021 by Politico and in the recent book “American Woman” by New York Times reporter Katie Rogers.

The Post was first to report the purported sexual component to bullying allegations against Bernal.

Five sources described general bullying allegations against Bernal to The Post. Four said they had heard Bernal speculate on the sexuality of colleagues, three relayed firsthand accounts of Bernal speculating on the genitalia of colleagues, and two said he shared with them a theory involving the size of a man’s thumb being proportionate to penis length.

The revelations about Bernal came to light hours after Politico reported that a different White House aide, associate director of presidential advance Ian Mellul, resigned March 1 after an investigation by the White House counsel’s office into allegations of verbal harassment.

Bernal’s critics said that internal tolerance of his conduct was inconsistent with Biden’s vow on his first day as president to fire aides “on the spot” if he hears that they have shown “disrespect” to people in their professional conduct.

“This is the second story in less than 24 hours about abuse and bullying by senior staff at the White House,” one source told The Post.

“At what point is Jeff held accountable for his own staff? That’s his entire job.”