Sri Lanka's acting President, Ranil Wickremesinghe, tells military to do 'whatever is necessary' to restore order

Sri Lankan protesters storm Prime Minister and acting President Ranil Wickremesinghe's office.

Sri Lanka's Prime Minister Ranil Wickremesinghe has told the military to do "whatever is necessary to restore order" after protesters stormed his office demanding that he resign.

He's been appointed acting president by President Gotabaya Rajapaksa, who fled to the Maldives on Wednesday, local time.

The decision to leave Mr Wickremesinghe in charge has triggered further protests in the island nation, which has been gripped for months by an economic meltdown that has triggered severe shortages of food and fuel.

Sri Lanka's president and its prime minister both agreed on Saturday to resign after protesters stormed their homes and set fire to a building.

However, neither has officially resigned and Mr Wickremesinghe appeared on television on Wednesday to reiterate that he would not leave until a new government was in place, although he urged the parliament's Speaker to find a new prime minister who will be agreeable to both the government and the opposition.

An injured protester is carried outside Sri Lanka's Prime Minister Ranil Wickremesinghe's office amid unrest in Colombo. (Reuters: Adnan Abidi)

It was not clear when that would happen, in part because the opposition is deeply fractured.

In his television appearance, Mr Wickremesinghe said he created a committee of police and military chiefs to restore order.

Acting Sri Lankan President Ranil Wickremesinghe has called for order. (AP: Eranga Jayawardena/ File)

Those who wanted Mr Wickremesinghe to resign had anticipated that he would be put in charge.

They rallied outside his office compound on Wednesday, and some scaled its walls.

The crowd roared its support for the people charging in and tossed water bottles to them.

"We need both … to go home," Supun Eranga, a civil servant in the crowd, said.

"Ranil couldn't deliver what he promised during his two months, so he should quit. All Ranil did was try to protect the Rajapaksas."

Police initially used tear gas to try to disperse the protesters outside the Prime Minister's office, but failed, and more marched down the lane toward the compound.

Protesters have demanded Ranil Wickremesinghe step down. (AP: Eranga Jayawardena)

Eventually, security forces appeared to give up, with some retreating from the area and others simply standing around the overrun compound.

Protesters lie on a bed after storming Mr Wickremesinghe's office. (AP: Rafiq Maqbool)

Inside the building, the mood was celebratory, as people sprawled on elegant sofas, watched TV and held mock meetings in wood-panelled conference rooms.

Some wandered around as if touring a museum.

ABC/AP