An ex-girlfriend of Ross Mirkarimi has come forward to police with new accusations of domestic violence against the San Francisco sheriff, law enforcement sources say.

The former girlfriend, Christina Flores, was dating Mirkarimi shortly before the then-supervisor met the woman who would become his wife, Venezuelan actress Eliana Lopez, at a conference in Brazil in 2008. Shortly after they met, Lopez became pregnant with the couple’s child.

Flores, who has hosted a talk show on local cable access and has appeared on television stations KOFY and KTVU, showed up at San Francisco’s Northern police station Sunday to file a police report describing an incident that she said happened at least three years ago, in which Mirkarimi allegedly shoved her against a wall, law enforcement sources said.

Flores, who lives in Southern California, told The Chronicle’s Rachel Gordon in a phone interview Monday that she had gone to police after reading accounts of the alleged domestic violence incident involving Mirkarimi’s wife. Her intent, she said, was to let authorities know that Mirkarimi’s alleged abusive behavior wasn’t a one-time, isolated occurence.

“If I need to testify, I will,” she said.

She said she dated Mirkarimi in 2007 and 2008. Several times, she said, he went on verbal tirades — “throwing tantrums, yelling in your face.”

Only one time, she said, did his anger turn physical. She said she doesn’t remember the details about the argument that led to the alleged attack, but does recall that her left arm was bruised.

“He never punched me, never hit me,” Flores said. “But he grabbed my arm and pushed me against the wall, yelling. This person is very much a pit bull and a bully.”

Mirkarimi’s attorney, Robert Waggener, said Monday that he had only just heard about the report and had not had a chance to talk to his client.

It’s doubtful Mirkarimi could be charged with a crime in connection with Flores’ report because the statute of limitations has probably expired. But her testimony could be used in Mirkarimi’s upcoming trial on three misdemeanor charges in connection with a New Year’s Eve incident involving his wife.

Lopez told a neighbor in a videotaped account that Mirkarimi had bruised her arm during the incident, but she has publicly denounced the criminal case and has not cooperated with prosecutors.

Flores’ account “can be used in a trial to show prior acts of violence and his propensity to put his hands on women, and theoretically she (Flores) could take the stand to say this is his M.O,” said a law enforcement official familiar with the case.

A judge set Mirkarimi’s trial Monday for Feb. 24.

The district attorney’s office declined to comment on Flores’ accusations.

“As a general rule, we don’t comment on an ongoing investigation,’’ said D.A. spokesman Omid Talai. “But we would welcome any information.’’