"The potential for an incident is very high today," he said. "Oil spills are caused mainly by ships and not only oil tankers."
He said oil produced in the Arabian Gulf is transported to the economies of east Asia passing the island.
"All these ships pass 5-6 km from Hambantota," Kularatne told a seminar on ocean resources organised by the Chamber of Construction Industry recently.
Hambantota is at the southern tip of the island where the government is building a port to take advantage of its proximity to the shipping route.
Kularatne said some 300 ships pass round the island daily.
"Some ships are not in the best seaworthy condition. They can meet with an accident especially during rough weather in the monsoon. If they cause an oil spill it will be disastrous."
Some of the island's best beaches that draw the tourists who bring in foreign exchange lie on the southern coast.
An oil spill could ruin the southern tourist industry.
The government's existing national oil spill contingency plan "does not work on the ground," Kularatne. "We tried it. So it is being revised."
One of the problems was lack of funds to get equipment and train people.
"Most importantly, an emergency fund is to be established," Kularatne said.
"This will be based on a levy that will be charged on ships calling at Sri Lankan ports because they are the potential polluters."