"The passing of this bill now means we will ably fight early child marriages in this country," Malawi Minister of Gender, Children and Social Welfare Patricia Kaliati told The Anadolu Agency (AA) in a phone interview.
"Early marriages are denying the girl-child the right to education," she complained.
On Thursday, lawmakers unanimously voted in favor of a much-awaited bill that outlaws marriage before the age of 18.
The Marriage, Divorce and Family Relations Bill streamlines earlier legislation on marriage and divorce and raises the legal age for marriage from 14 to 18.
It is expected to soon be signed into law by President Peter Mutharika.
Malawi reportedly ranks eighth in the world in terms of early child marriages, with some girls as young as nine married off because their parents are too poor to feed and clothe them or pay for their education.
Most of these young girls end up being abused; others die while giving birth.
Some suffer from birth-related complications that lead to a condition known as fistula.
A majority of these girls do not finish their education and remain trapped in poverty.
In 2001, a Special Law Commission was instituted to review laws on marriage and divorce.
It took the commission years to draft the bill, which was later rejected by the cabinet because it also included a prohibition on polygamy.
This time around, Kaliati said, the bill had the support of MPs, especially on the marriage age, which has remained a contentious issue since a proposal to increase it to 16 was shot down several years ago.
Several MPs told AA that they had supported the bill because of Malawi's high rate of child marriages.
"Something had to be done to stop this malpractice. That is why I supported the bill," MP Lucius Banda of the United Democratic Front, told AA.
The opposition Malawi Congress Party, for its part, described the new legislation as a "triumph" for democracy.
"The bill is important as it safeguards the rights of our girls," party spokesperson Jessie Kabwila told AA. "Our girls must be in school, not forced into marriage."
Emma Kaliya, head of the Gender Coordination Network, could not hide her excitement.
"It has been a long battle, but we finally have a law that will support our fight for the girl-child," she told AA, going on to vow: "We will intensify the campaign against early marriage."