"There have been no reports of any fighting," Brigadier Nahil Jayakody, the military spokesman in Colombo, said.
As the guns fell silent, the rebels said a ferry service would resume in a previously off-limits lagoon from today. It will link the rebel-held northern Jaffna Peninsula with the mainland.
Tamil civilians reaching Vavunia, a mainland town 135 miles north of Colombo, said they heard announcements about the ferry service over rebel radio.
The military had declared the lagoon off-limits in 1990. The rebels had been transporting people to the mainland at night to avoid detection by the security forces.
Shortly after the ceasefire, rebel leaders in the north tuned their radios on to military channels and exchanged messages of greetings with their opponents on the government side.
The truce, the first in nearly five years, brought a halt to the fighting in Sri Lanka's brutal 11-year ethnic war, which has killed more than 34,000 people.
The two-week ceasefire is due to expire the day after Pope Paul II ends a 24-hour visit to Sri Lanka.
The brevity of the truce indicates the depth of distrust between the two sides. Government and guerrilla negotiators are to review the truce next Saturday.
"I pray that this will be the dawn of a new era of peace for our long-suffering nation," President Chandrika Kumaratunga said when she announced the truce on Friday.
The accord, signed by Mrs Kumaratunga and the rebel chief Velupillai Prabhakaran, was negotiated on Tuesday in the guerrilla stronghold of Jaffna in the north. A direct radio link was established between the president and the rebel leader, the state-run Sunday Observer newspaper said.
The rebels have been fighting for a separate homeland in northern Sri Lanka. Tamils say the ethnic Sinhalese-dominated government denies them jobs, education and a fair share of the island nation's wealth. Tamils comprise 18 per cent of Sri Lanka's 17 million people.
The government hopes the truce will be the prelude to political negotiations. It says it has prepared proposals offering broad of autonomy for Tamil-dominated provinces but falling short of statehood. The guerrillas have not yet agreed to political talks.
The truce is being monitored by government and rebel representatives. The Dutch and Norwegian governments have agreed to help monitor the accord.