In an explosive allegation unleashed the morning after the first gubernatorial debate, a lawyer for Republican Meg Whitman’s former housekeeper said the candidate for governor knew the woman was probably an illegal immigrant for years and fired her only after she launched her campaign.

Los Angeles attorney Gloria Allred said today that the housekeeper, Nicandra Diaz Santillan, who went by the name Nicky Diaz, was “exploited, disrespected, humiliated and emotionally and financially abused” by Whitman, the billionaire former eBay CEO who is running against Democrat Jerry Brown.

In an tearful appearance at a news conference in Los Angeles, Diaz said Whitman had callously dismissed her because she feared it would hurt her chances of being elected governor. “She treated me as if I was not a human being,” she said.

Allred said at the same news conference that the Social Security Administration sent Whitman a letter dated April 22, 2003, saying the Social Security number provided by the housekeeper did not match the name on file.

Allred said, “Nicky was told to ‘check on this.”’

The attorney did not make clear whether it was Whitman or her husband who allegedly told her that.

“Nicky also alleges that for several more years, Ms. Whitman continued to receive letters from the Social Security Administration office regarding the mismatch in the Social Security numbers,” Allred said. “She alleges that she saw these letters after they were thrown in the trash.”

Whitman, however, told reporters during an appearance at Cisco Systems in San Jose that she had received no notification from any government agency of any discrepancy between the Social Security number and the name.

“We never received that letter or that notification,” she said, adding the housekeeper was hired through an employment agency that she relied on to check the worker’s information. The Whitman campaign said the employment agency’s form contained Social Security and driver’s license numbers.

Lowell Kepke, a spokesman for the Social Security Administration, said in an e-mail to the Mercury News that he couldn’t confirm or deny that a “no-match letter” was sent to Whitman’s household because “wage and tax data” is protected by the Internal Revenue Code.

“I feel bad for her, she’s being manipulated, I think, and I’m sorry for that,” Whitman said. “Everything Gloria Allred is saying is a lie.”

Whitman said she fired the woman as soon as she said in June 2009 that she was in the country illegally. “No one could’ve been more stunned than I was,” Whitman said.

Whitman says the incident underscores the need for an eVerify system to check workers’ documentation. She said she didn’t disclose the situation herself while on the campaign trail because she didn’t want to make a public example of someone who had been so close to her family.

Asked what should happen to the woman now, Whitman said that’s up to federal immigration authorities.

Because Diaz now could face deportation by coming forward, Allred called Diaz’s decision to speak out “the most courageous decision I’ve seen in 35 years of practicing law.”

Allred said she was only recently contacted by Diaz, who got her name from another attorney’s referral.

Family members at the Union City home of the woman would not talk to reporters, citing advice from Allred.

The Whitman campaign tried to blunt the impact of Allred’s news conference by holding its own a half-hour earlier and releasing Diaz’s employment form.

“What’s a California governor’s race without Gloria Allred inserting herself?” said campaign senior adviser Rob Stutzman.

He said he found it “really curious” that the news conference was held the day after Whitman performed well in a debate with Brown, who Stutzman said is a “personal friend” of Allred and a campaign donor.

“The timing is curious,” he said. “This is the post-debate smoke bomb.”

But the allegations are sure to roil the campaign and threaten to undermine one of Whitman’s main political goals: to attract a relatively large share of the Latino voting population to overcome the Democrats registration advantage.

“This has to hurt badly,” said Jaime Regalado, director of the Pat Brown Institute of Public Affairs at California State Los Angeles. “This could cut away at the credibility of her attempt to reach out to Latinos.”

If Whitman’s response comes off as harsh, there could be an even more resounding boomerang effect, Regalado said. It also plays into the characterization of Whitman as a bullying CEO, someone who mistreats those below her.

“If she responds with character assassination, it’ll play out for a longer time,” Regalado said. “It will be contentious, bullying Meg Whitman and it will remind some of the shoving incident.”

Earlier this year, a New York Times story reported that she had to pay a $200,000 settlement to a former employee for shoving an employee.

Whitman’s hopes of containing the potential damage rests on whether Allred can prove that Whitman knew her employee was an undocumented worker, said Jack Pitney, government professor at Claremont McKenna College.

“The open question is whether people will see this as a legitimate outpouring of somebody in difficult straits or if they’re being manipulated by the Brown campaign,” Pitney said. “It has the potential to be hurtful or it could be just a passing episode.”

Brown’s campaign kept its distance from the allegations, sensitive to the charges that Allred is trying to bolster Brown, whom she has contributed $1,150 over the years, including $150 in 2006 and $1,000 in 1982. She said on CNN in 2007 that she knows Brown “personally.”

Steve Russell, one of Whitman’s next-door neighbors, said he wasn’t aware the Republican gubernatorial candidate even had a housekeeper. He said he has witnessed Whitman mowing her own lawn and power-washing the picket fence around her two-story, cream-colored house.

Even if the allegations are true, “I do not find it hypocritical at all,” said Russell, who described himself as a “Non-Republican” who intends to vote for his neighbor.

Contact Ken McLaughlin at kmclaughlin@mercurynews.com. Mercury News staff writer Joe Rodriguez contributed to this report.