Sirisena's election last month had been expected to lead to a lessening of the numbers of troops in towns and cities -- particularly in former war zones -- which had been a prominent feature of his predecessor Mahinda Rajapakse's tenure.
During the build-up to his election victory, Sirisena promised to confine the military to their barracks and call them out only in the event of an emergency or a threat to national security.
"By virtue of the powers vested in me, I, Maithripala Sirisena, do by this order call out all the members of the armed forces...For the maintenance of public order," read the order.
The presence of large numbers of troops is particular contentious in the mainly Tamil northern and eastern provinces that bore the brunt of a 37-year separatist conflict, which was brutally crushed by the army in May 2009.
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During a speech yesterday to mark the 67th anniversary of the former British colony's independence, Sirisena had stressed his desire for a national reconciliation which Rajapakse is accused of failing to deliver.
"We have been asking for the withdrawal of troops from the north and the east, but this order only serves to continue the army presence," Premachandran told AFP.
"I strongly believe that there is no need to deploy troops anywhere in the country. He (Sirisena) promised change but if he is going to continue what the previous government did, then we are back to square one," he said.
The Free Media Movement (FMM), a leading local rights groups, said it had expected Sirisena to confine troops to barracks.
Sri Lanka lifted a state of emergency in August 2011, two years after security forces crushed Tamil Tiger rebels and declared an end to war but the previous government had deployed the military alongside the police.