During her four-year term, together with the mayors of Las Condes (Joaquín Lavín) and Santiago (Jaime Ravinet), she founded the Chilean Association of Municipalities [es], becoming its first vice president.

[1] Pérez was presented as a candidate for the Chamber of Deputies in the 1997 parliamentary election, for District 26, corresponding to the commune of La Florida.

On that occasion, she was a member of the permanent commissions of national defense, housing and urban development, foreign relations, interparliamentary affairs, and Latin American integration.

[1] In 2005, Pérez was a candidate for senator for the Santiago Oriente constituency in that year's parliamentary election, but did not win a seat.

[1] In December 2009, she was elected senator on behalf of RN, for the Valparaíso Cordillera Region (Constituency 5) with the first majority within the Coalition for Change.

[4] On 16 January 2014, she resigned from her membership in RN, accusing its board of directors, headed by Carlos Larraín, of "intolerance, classism, and personalism.

[7][8] She is a supporter of abortion on three grounds - when the mother's life is at risk, when the fetus will not survive the pregnancy, and in the case of rape.