Approval for Muslim women to join the military came after Sri Lanka - 's military last month began recruiting for the exclusively Muslim unit.
The unit will protect Muslims living in the troubled Ampara province where Tamil Tiger rebels, who are mostly Hindus, want to extend their domination.
Military spokesman Brig. Sudhir Samarasinghe said Muslim women will be recruited to join the forces in interviews this week.
Muslims are Sri Lanka - 's second-largest minority after ethnic Tamils and generally oppose the Tamil Tigers, who have accused Muslims of supporting the government. The rebels also oppose Muslims cultivating land in areas they consider Tamil territory.
During two decades of civil war, the rebels carried out systematic killings of Muslims, including a massacre in August 1990 of 130 Muslims at two mosques on the same day.
Tens of thousands of Muslims fled the northern Sri Lanka - 's Jaffna Peninsula after the rebels started their separatist campaign there in 1983.
More than 65,000 people were killed in the conflict before a Norway brokered cease-fire signed in 2002.
The truce has come under severe strain due to spiraling violence, with more than 166 people, including 87 government security personnel, killed since December.
Both sides agreed in Geneva, Switzerland last month to scale down violence and will meet again for talks on April 19-21.
Women from Sri Lanka - 's majority ethnic group the Buddhist Sinhalese are also allowed to join the country's military, while the rebels are known to have a large number of female fighters.