Raising the retirement age, increasing workers' pension contributions, and reducing some workers' pension benefits have provoked strong opposition.
Brazil's lower house of Congress approved Wednesday a highly controversial overhaul to the country's pension system with 379 votes in favor, 131 votes in opposition - more than the 308 needed for it to pass.
The vote was moved forwards despite massive protests last month, with hundreds of other social movements, student organizations, asnd twelve of the country's largest trade unions mobilizing against the reform.
Bolsonaro's social security reform bill, which he says will restore public finances, seeks to raise the minimum retirement age and workers' contributions. It also includes provisions that eliminate labor protections for pregnant women and breastfeeding mothers.
Currently, in Brazil, workers receive a full retirement that is 80 percent of their highest contribution during the 35 years of contributions, for men, and 30 years, for woman.
If the proposal is approved by Brazil's Senate, the minimum retirement age will be 62 for women and 65 for men.
Meanwhile, Brazilian markets cheered the prospect of a bill passing when the voting session opened around midday on Wednesday.
By then, Brazil's benchmark Bovespa stock market had already jumped nearly 2 percent to an all-time high above 106,000 points and the currency had hit its strongest level since March as traders bet the long-awaited approval was within reach.
Pension reform is the cornerstone of President Jair Bolsonaro's neoliberal economic agenda.
The second round of lower house voting will expected to take place on Friday, before Congress breaks for recess on July 18. That would set up the Senate to begin debating the bill in August, after returning from recess.