After the first multiparty elections in 1994, she became member of the National People's Assembly for the RGB-MB. The RGB-MB became the largest opposition party in parliament, conquering 19 out of 100 seats. Zinha Vaz was one of ten women legislators. Two of her family members also conquered seats for the RGB-MB, her brother Fernando Vaz and cousin Hélder Vaz Lopes. As a member of parliament Zinha Vaz focused on fighting corruption and abuse of power by government officials. She also tried to further the role of women in Guinea-Bissau society. As a member of the Permanent Commission of the National People's Assembly Zinha Vaz tried to mediate between President João Bernardo Vieira and Brigadier-General and coup-leader Ansumane Mané in the Guinea-Bissau Civil War of 1998–1999.