"We need to change the rules of the pension system. People are living longer and women have fewer children, which means that the working population will decrease," Leonardo Rolim, the official responsible for pensions at the Economy Ministry, told a news conference.
The text, which requires constitutional changes to impose a minimum retirement age and extended pay-in periods for workers in both the public and private sectors, is a crucial plank of President Jair Bolsonaro's plan to overhaul Latin America's biggest economy.
The president personally went to Congress on Wednesday to hand over a draft of the text.
The retirement age -- which is not provided under the current system -- would be set at 62 for women and 65 for men.
The minimum contribution period has been set at 20 years, but it will take 40 for participants to receive a full pension.