SRI LANKA'S ousted president, Gotabaya Rajapaksa, is expected to arrive in Thailand on Thursday, seeking temporary shelter in a second Southeast Asian country after fleeing his island nation last month amid mass protests, two sources said.

Rajapaksa fled to Singapore on July 14, via the Maldives, following unprecedented unrest triggered by Sri Lanka's worst economic crisis in seven decades and days after thousands of protesters stormed the president's official residence and office. 

The retired military officer then resigned from the presidency, becoming the first Sri Lankan president to quit mid-term.

The former president is expected to leave Singapore and go to Thailand's capital Bangkok on Thursday, two sources said, asking not to be named.

Sri Lanka's foreign ministry did not immediately respond to requests for comment. Thai government spokeswoman Ratchada Thanadirek told Reuters “no comment”.

Rajapaksa has not made any public appearances or comments since leaving Sri Lanka, and Singapore's government said this month that the city-state had not accorded him any privileges or immunity. 

A member of the influential Rajapaksa family, the 73-year-old served in the Sri Lankan military and later as defence secretary.

During his time as defence secretary government forces finally defeated Tamil Tiger rebels in 2009 to end the Sri Lankan civil war. Some rights groups now want accusations that Rajapaksa committed war crimes to be investigated. Rajapaksa has previously strenuously denied the allegations. 

Some critics and protesters also accuse Rajapaksa and his family of mishandling the economy during his term as president, leading to the country's worst financial crisis since independence from Britain in 1948.

His elder brother, Mahinda Rajapaksa, is a former president and prime minister. Their younger sibling, Basil Rajapaksa, served as finance minister till earlier this year.

Rajapaksa's successor, Ranil Wickremesinghe, has previously indicated that the former president should refrain from returning to Sri Lanka in the near future.

"I don't believe it's the time for him to return," Wickremesinghe told the Wall Street Journal in an interview on July 31. "I have no indication of him returning soon."

If Rajapaksa returned to Sri Lanka, he might not be protected under law if any charges were filed against him, legal experts have said.