SACRAMENTO — California senators will no longer review complaints of sexual harassment against themselves or their staff under a new rule announced by state Senate President Pro Tem Kevin de León and other lawmakers.

Instead, he and other members of the Senate Rules Committee said they will send “complaints, allegations and open investigations, including the most recent allegations against a sitting senator” to an independent outside law firm for investigation.

De León, a Los Angeles Democrat, made the change following allegations against his roommate, state Sen. Tony Mendoza, D-Artesia (Los Angeles County), by two of his former female employees. On Saturday, de León moved out of the home they shared a short drive from the state Capitol.

“The people who work here and the public we serve must have complete confidence that no public official is above the law or our strict zero-tolerance harassment policies,” de León said. “Those who violate these policies will be held to account — swiftly and justly.”

The allegations against Mendoza, first reported in the Sacramento Bee, involve a 23-year-old Cal State Sacramento fellow who says the 46-year-old senator repeatedly invited her to his home when she went to him looking for a permanent job and suggested she stay in his hotel during a fundraiser.

Mendoza denied any wrongdoing, saying he would “never knowingly abuse my authority nor intentionally put an employee into an awkward or uncomfortable position.” He did not respond to whether he invited the woman home with him.

A second employee alleged that in 2008 when she was a 19-year-old intern in Mendoza’s office, he singled her out by flying her to San Jose for the Democratic convention and asked her to have a drink at a minibar in his hotel suite, where he booked her an adjoining room. The woman, Jennifer Kwart, said Mendoza’s behavior made her so uncomfortable that she made up a reason to fly home, according to the Bee.

Kwart, who now works for Assemblyman David Chiu, D-San Francisco, said she only came forward with her allegation against Mendoza after reading that another woman had a similar experience.

“I wanted her to know that she was not alone,” Kwart wrote on Twitter, adding that she had no further comment beyond what she shared with the Bee.

Chiu said he stands by Kwart and knows her as a “professional of utmost integrity” who took a “courageous step of speaking out publicly.”

“The Legislature needs to conduct a full, immediate and independent investigation of this matter, and there need to be real consequences,” Chiu said. “Coupled with recent allegations and continued denials, I have serious doubts about whether the senator should continue to serve in public office.”

Mendoza said in a statement that Kwart’s allegation is “completely false.”

Mendoza was first elected to the Assembly in 2006 and then moved to the Senate in 2014 to replace Sen. Ron Calderon, who is serving a prison sentence for corruption. Mendoza, a married father of four, is up for re-election in 2018.

The latest allegations come after more than 300 women who work in California politics signed a letter last month saying they have “endured, or witnessed or worked with women who have experienced some form of dehumanizing behavior by men with power in our workplaces.” Most have chosen not to name names. Their grievances followed a recent movement among women in Hollywood identifying men who have been frequently accused of sexual assault and harassment, including the powerful film industry mogul Harvey Weinstein.

De León, who is trying to unseat U.S. Sen. Dianne Feinstein in the 2018 election, is facing questions about what he knew and how he handled sexual harassment complaints in the state Capitol during his three years leading the Senate.

De León spokesman Jonathan Underland said de León was unaware of allegations against Mendoza until they were reported by the media.

The allegations of sexual misconduct aren’t limited to the Senate. Another lawmaker, Assemblyman Raul Bocanegra, D-San Fernando Valley, was quietly disciplined eight years ago when he was an Assembly legislative staffer after a female staffer accused him of groping her.

The Assembly will hold hearings beginning Nov. 28 to review its policies and seek recommendations on how to improve its own process.

Complaints against lawmakers or staff were previously handled internally by a rules committee in both houses that is controlled by lawmakers.

Legislative staffers have said they do not feel comfortable making complaints to the committee out of fear of retaliation since they are at-will employees who can be fired for any reason.

Melody Gutierrez is a San Francisco Chronicle staff writer. Email: mgutierrez@sfchronicle.com Twitter: @MelodyGutierrez