Defence Secretary Gotabhaya Rajapakse, who is President Mahinda Rajapakse's younger brother, said Tiger sympathisers outside the country were trying to revive the Tamil separatist movement.
"The security forces, police and intelligence services must take certain steps to ensure that terrorism does not raise its head again in this country," he said.
"Our intelligence networks have to be developed and intelligence gathering enhanced."
He said the navy must also strengthen its coastal patrols to ensure weapons were not smuggled in by sea. At the height of their power, the Tigers had both air and sea capability, and controlled a third of the island.
Gotabhaya said although the Tigers had not carried out any attacks since the group's leadership was wiped out a year ago this week, the pro-rebel lobby abroad was still active.
"The motive of these international groups remain the same as that of the LTTE (Liberation Tigers of Tamil Eelam)," he said in a statement marking the first