Hundreds of workers have marched in the Malawi capital, Lilongwe, against a bill which seeks to set the retirement age at 55 for women and 60 for men.
If passed, it would become compulsory for workers to have a pension fund.
But unions say the fund would not benefit Malawians, who have an average life expectancy of about 50.
The Malawi Congress of Trade Union (MCTU) wants pensions to be paid at 45 or after a set number of years employment at a company.
Some 300 workers marched to parliament to hand over a petition demanding changes to the current bill.
"If someone has been working for a company for 20 years they should be able to access their pension," the union's general-secretary Robert Mkwezalamba told the BBC's Network Africa.
But Labour Minister Yunus Mussa says the pension package is mainly aimed at instilling a culture of saving among Malawians.
"Right now people work for years and they only get a token of appreciation - a radio, a blanket or bicycle. We are saying people should contribute to that so that when they retire they do not suffer."
Mr Mussa dismissed the union's claims that no one would benefit from the scheme.
"It will be a law and everybody should comply… those people who do not comply will face heavy penalties."
"There are people in Malawi older than 50, 70. They are still productive citizens of the country," he said.