Brosas was a member of the Philippine House of Representatives for the 18th Congress under the Gabriela Women's Party-list group, during which she served as assistant minority leader. She filed the Rice Industry Development Act, which aims to support Filipino farmers and identify rice zones to boost rice production in the country. She also filed in the 18th Congress a Magna Carta for Daycare Workers, Amendments to the Solo Parents Welfare Act, Amendments to the Anti-Rape Law, and Electronic Violence Against Women and Children. In 2020, Brosas joined fellow lawmakers in protesting the passage of House Bill number 6875, also known as the anti-terror bill. In 2021, she opposed Resolution of Both Houses No. 2 that aims to amend economic provisions of the 1987 Constitution on foreign ownership of key industries. Brosas supports
climate justice and the protection of human rights. == 19th Congress ==