Restrictive land policies have also prevented consolidation.
Rice is water intensive and needs full inundation during part of its growth cycle.
Earlier this week, Sri Lanka's Geological Survey and Mines Bureau warned that paddy cultivation in the northwest Puttalam district was lowering the water table in the area and there was a threat of sea water contamination of ground water resources.
"We feel there might be an artificial shortfall in rice supply, so the government is going to import 50,000 metric tons of rice as a buffer stock," information minister Anura Yapa told reporters.
"This will be kept as a buffer stock if there is an increase in price. We are not just importing rice it will be released to the market if there is a spike in prices."
Sri L