According to UNICEF, Pakistan has nearly 19 million child brides.
The UN children's agency estimates that around 4.6 million were married before the age of 15 and 18.9 million before they turned 18.
Yasmin Lehri, a former lawmaker from Baluchistan's capital Quetta, said almost all girls in rural and tribal areas of the province were married before the age of 18.
"In urban areas, because of growing awareness, girls are married at 18 or older but in the rest of the province the situation is very grim," she said.
Lehri explained that poverty and economic factors played a significant role, with young girls often exchanged between families to work as laborers.
Pakistani lawmaker Kishwar Zehra said the country's religious right was the biggest opposition to a law stipulating a minimum marriage age.
"When a bill setting an age limit was presented in the national assembly's committee, it was strongly opposed by religious-minded lawmakers," she explained.
Maulana Sherani, a former chairman of the Council of Islamic Ideology, has publicly opposed any law setting the minimum age of marriage for girls. The council advises the government on the compatibility of legislation with Islam. In 2014, the council declared child marriage restraint laws "un-Islamic."
When a bill establishing a minimum age was presented in the Baluchistan assembly, religious parties also opposed it.