Sri Lanka's new president Ranil Wickremesinghe has formally invited MPs to join an all-party unity government to revive the bankrupt economy by undertaking painful reforms, his office said on Sunday.

Wickremesinghe took office earlier this month after public anger over the island nation's worst economic crisis forced his predecessor Gotabaya Rajapaksa to flee the country and quit.

Explainer: How Sri Lanka spiralled into crisis

In a meeting on Saturday with the influential monks of the Temple of the Tooth in Kandy, one of Buddhism's most sacred shrines, Wickremesinghe outlined his plans.

“As the president, I wish to start a new journey,” Wickremesinghe was quoted as telling the monks in his first meeting with the powerful Buddhist clergy since taking office.

“I would like to get all the parties together and go on that journey as well as to form an all-party government.”

He has written to all lawmakers asking them to join a unity government.

A former opposition MP, Wickremesinghe, 73, took up the premiership for the sixth time in May after Rajapaksa's elder brother Mahinda resigned and there were no other takers for the job.

Wickremesinghe went onto become the president after Gotabaya escaped on July 9 when tens of thousands of protesters angry at the economic crisis stormed the presidential palace.

He fled to Singapore from where he resigned five days later and Wickremesinghe became interim president and later won a vote in parliament confirming his ascension.

Sri Lanka's 22 million people have endured months of lengthy blackouts, record inflation and shortages of food, fuel and medicines. Since late last year, the country has run out of foreign exchange to finance even the most essential imports.

In April, Sri Lanka defaulted on its $51 billion foreign debt and opened bailout talks with the International Monetary Fund.

Wickremesinghe told monks that the economy would decline further this year with a contraction of 7.0 per cent, but expected a recovery next year.

“I am working to re-stabilise this economy and build the economy in such a way that the country can be developed by 2023, 2024.

“It is a difficult task. But if you don't do it now, it will be more difficult. We should think about whether we should try to cure the patient by giving medicine or let the patient die without giving medicine,” he added.

He said inflation currently running at 60.8pc could go up further.

After his election as president, Wickremesinghe, while ordering security forces to clear protest sites, has appointed an interim cabinet leaving the door open for others to join.

He has called a new session of parliament from Wednesday and is expected to expand the 18-member cabinet to accommodate members from opposition parties.