Ginger Lee said she and Weiner exchanged about 100 emails between March and June, beginning after Lee posted a supportive statement about the congressman on her blog. She said they mostly discussed politics, but he would often turn the conversation to sex.
"'I have wardrobe demands too. I need to highlight my package,"' Weiner wrote Lee, in an email read aloud at the news conference by Lee's attorney, Gloria Allred.
Weiner acknowledged last week that he had sent lewd photos and texts to women after a photo of his crotch was posted on Twitter. In an interview two weeks ago, he acknowledged that he had exchanged messages with Lee but didn't elaborate.
Lee said she did not send sexually suggestive messages to Weiner.
"Anytime that he would take our communications in a sexual direction, I did not reciprocate," she said.
Weiner sent Lee an email after the photo of his crotch was sent out on his Twitter account, and "he asked me to lie" about their contact, she said.
Lee said she put out a three-sentence statement on the matter at his request. She said she then went into hiding and on June 2, he called her and told her to avoid press.
She said she was coming forward now to tell the truth and to deny reports that she was in an online sexual relationship with him.
Allred is a Los Angeles attorney who has represented figures in high-profile sex scandals, including a woman who said she was a girlfriend of Tiger Woods and a former child actress who said she had an affair with former Gov. Arnold Schwarzenegger.
A Weiner spokeswoman did not immediately return a request for comment. Weiner has taken a two-week leave from the House, in treatment for an undisclosed disorder at an undisclosed location.
House Democratic colleagues are looking for him to step down this week amid a growing chorus for him to resign. Even President Barack Obama has suggested he should leave.
Adding to the drama, Weiner's pregnant wife, Huma Abedin, returned Wednesday from a trip to Africa with her boss, Secretary of State Hillary Rodham Clinton.
A fellow member of Weiner's New York Democratic delegation, Rep. Carolyn McCarthy, said she's heard from Weiner's friends that the congressman was waiting for his wife to come home before making any decisions about his political future. McCarthy also cited talk among Weiner's friends about the possibility he could resign this week.
House Democrats huddled behind closed doors Tuesday for their regular party meeting, but they decided against taking action against Weiner in hopes that he'll resign soon.
The House Democratic leader, Nancy Pelosi, reiterated her call for Weiner to quit, saying after the meeting that she wanted to make sure nobody missed her earlier resignation call while members were on a weeklong recess.
Rep. Sander Levin, D-Mich., said: "I think we should send a strong message to him that he should resign, and let's see what happens. The more of us who say it, the more telling it will be."
House Speaker John Boehner, a Republican, had been content to let Democrats wrestle with the embarrassing scandal, but when asked Tuesday whether Weiner should resign, he responded, "Yes."
The furor over sexually suggestive photos and other revelations about the 46-year-old congressman has been a distraction for Democrats seeking momentum as they gear up for the 2012 elections. Besides Pelosi, several other Democrats have called for Weiner to quit, including the party chairwoman, Rep. Debbie Wasserman Schultz, D-Fla.
Associated Press writer Andrew Miga in Washington contributed to this report.