Sri Lanka's acting President Ranil Wickremesinghe gazetted orders late on Sunday for a state of emergency in the crisis-ridden island nation, in an effort to head off unrest ahead of a vote in parliament later this week to elect a new president, Reuters reported.

"It is expedient, so to do, in the interests of public security, the protection of public order and the maintenance of supplies and services essential to the life of the community," the notification stated.

Wickremesinghe had announced a state of emergency last week, after president Gotabaya Rajapaksa fled the country to escape a popular uprising against his government, but it had not been officially notified or gazetted.

Previous emergency regulations have been used to deploy the military to arrest and detain people, search private property, and dampen public protests.

Rajapaksa fled to the Maldives and then Singapore last week after hundreds of thousands of anti-government protesters came out onto the streets of Colombo a week ago and occupied his official residence and office.

The Sri Lankan parliament accepted Rajapaksa's resignation on Friday, and convened a day later to begin the process of electing a new president, with the vote set for Wednesday.

Wickremesinghe, a six-time prime minister regarded as an ally of Rajapaksa, is one of the top contenders to take on the presidency full-time; but protesters also want him gone, leading to the prospect of further unrest should he be elected.