Amid hectic parleys to form a new government in Sri Lanka, Opposition Leader Sajith Premadasa said on Thursday that he would accept President Gotabaya Rajapaksa's invitation to form a new government if he agrees to some conditions, including his resignation within a stipulated time period.

In a letter to the President on Thursday, 55-year-old Premadasa said that the Samagi Jana Balawegaya-led Opposition is willing to form a new interim government in Sri Lanka subject to conditions.

"One of the conditions put forward by Sajith Premadasa is that the 19th Amendment to the Constitution should be implemented with the support of all political parties within two weeks. Further, President Gotabaya must resign within a stipulated time period," local media reported, citing the content of the letter.

The third condition is that the President should work together with all the political parties to work towards abolishing the Executive Presidency via the 21st Amendment to the Constitution.

The fourth condition is that the President must call for Parliamentary Elections to give the people an opportunity to elect a new stable government, following the implementation of the aforementioned constitutional reforms, establishing the rule of law, and returning the people's lives to normalcy.

Premadasa said that he has a sustainable programme to control the fall of the economy and for the implementation of the constitutional reforms.

He said he is prepared for discussions on the swearing in of the new government, and on the period of the said new government.

His comments came amidst reports that four-time former prime minister Ranil Wickremesinghe, who has just one seat in the 225-member Parliament, could be sworn-in as the next premier on Thursday.

The 73-year-old United National Party (UNP) leader held talks with President Rajapaksa on Wednesday and is expected to meet him again on Thursday.

Premadasa, who was part of the UNP and served as minister under Wickremesinghe, had parted ways and became the main Opposition.

In a late-night televised address to the nation, the President on Wednesday refused to quit but promised to appoint a new Prime Minister and a young Cabinet this week which would introduce key constitutional reforms to curb his powers, amid protests over the nation's worst economic crisis that ousted his elder brother Mahinda Rajapaksa who is under protection at a naval base following violent attacks on his aides.

Sri Lanka is facing its worst economic crisis since gaining independence from Britain in 1948. The crisis is caused in part by a lack of foreign currency, which has meant that the country cannot afford to pay for imports of staple foods and fuel, leading to acute shortages and very high prices.

Thousands of demonstrators have hit the streets across Sri Lanka since April 9 seeking the resignation of the Rajapaksa brothers.