Former Sri Lankan president Gotabaya Rajapaksa has requested entry into Thailand for a temporary stay in a second Southeast Asian country after fleeing his island nation last month amid mass protests, the Thai foreign ministry said on Wednesday.

Rajapaksa fled to Singapore on July 14 following unprecedented unrest caused 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 head of state to quit mid-term.

Rajapaksa is expected to leave Singapore and head 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.

Tanee Sangrat, a Thai foreign ministry spokesman, said Rajapaksa holds a diplomatic passport that allows him entry into the country for 90 days. He did not say when Rajapaksa intended to visit.

"The entry to Thailand by the former president of Sri Lanka is for a temporary stay," Sangrat said.

"The Sri Lankan side informs us that the former president has no intention for political asylum in Thailand and will travel to another country afterwards."

Rajapaksa has made no public appearances or comments since leaving Sri Lanka, and Reuters was unable to immediately contact him.

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 a bloody 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 South Asian 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 until earlier this year.

Rajapaksa's successor, Ranil Wickremesinghe, has suggested 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 came back to Sri Lanka, he might not be protected under law if any charges were filed against him, legal experts have said.