Margarita Lopez, the Lower East Side’s new councilwoman, has 20 years experience as a tenant organizer and low-income housing advocate. But those credentials weren’t good enough to earn her a seat on the council’s Housing and Buildings Committee.

Council Speaker Peter Vallone, who parceled out committee assignments in early January, rejected Lopez’s request to sit on the housing panel-even though her Lower east Side predecessor Antonio Pagan enjoyed the honor.

“It’s very sad that consideration was not given to my expertise in that area,” said Lopez, who narrowly defeated state Assembly Speaker Sheldon Silver’s handpicked candidate for the seat last fall. “But if anyone thinks that means that I won’t be involved in the issues before that committee, they are mistaken.”

Lopez has instead been assigned to sit on Youth Services, Civil Service and Labor, Contracts and Women’s Issues. “We try to accommodate people as best we can,” explained Vallone spokeswoman Rica Rinzler. “And any councilmember is certainly free to attend any committee hearing they want.”

Meanwhile, Vallone, who is seeking the Democratic nomination for Governor, elevated the women’s subcommittee to full committee status and reinstated Upper West Side Democrat Ronnie Eldridge as it chairwoman. Vallone stripped that post from Eldridge in 1995, retaliating against the progressive’s repeated “No” votes on Vallone budgets.

In other council committee changes: Helen Marshall, a former Queens assemblywoman, has been picked to chair the council’s newly established Higher Education Committee. Lucy Cruz, who has been investigated by the council for ethics problems, was appointed to the top of the council’s civil service committee. Bronx Democrat Larry Warden, a possible candidate for Jose Serrano’s South Bronx congressional seat, replaces Pagan as chairman of the housing committee’s subcommittee on Abandonment, Foreclosure and Disinvestment. Martin Malave-Dilan, a low-key rep from East Brooklyn gets to occupy the a moral perch in his bid to unseat Congresswoman Nydia Velazquez–he’s the new council ethics chairman.