Among the oil firms that showed interest were 11 independent and national oil firms.
Petroleum ministry officials presented the model petroleum resources agreement to oil and gas companies and also held separate meetings with them.
The government is offering three exploration blocks in the Mannar Basin, each about 3,500 square kilometers in area for oil and gas exploration companies.
Two separate blocks have already been offered to Indian and Chinese state oil firms.
The government says recent seismic surveys have indicated the presence of petroleum deposits in the Gulf of Mannar.
It has said that India's drilling of oil on her side of the maritime boundary strengthens the possibility of striking oil in Sri Lankan waters.