Jocelyn Chia told the joke during a set at the Comedy Cellar in New York City, the US, reportedly in April, as she riffed on the historically testy relationship between Malaysia and Singapore, where she was raised.

MH370 went missing in March 2014, and is one of Malaysia's deadliest aviation incidents, with all 239 people on board presumed dead.

Such was the outrage over Chia's joke that Malaysian police began an investigation under incitement and offensive online content laws.

On Tuesday Malaysia's police chief Acryl Sani Abdullah Sani said they would ask Interpol to help locate her, according to Malaysian news agency Bernama.

The head of police in the southern state of Johor said in a statement that a request had been filed on Wednesday. Kamarul Zaman Mamat said they were seeking "further information regarding the suspect to assist in investigations."

Chia is being probed under public mischief laws that carry a jail term of up to two years, as well as communications legislation under which offenders face up to a year in prison.

Malaysia and Singapore were briefly one state after the end of British colonial rule, but they separated in 1965.

Chia, who has roots in Singapore, said in her routine that the city-state had since become a "first-world country" and that Malaysian "airplanes cannot fly".

"Malaysian Airlines going missing not funny, huh," she continued. "Some jokes don't land."

It caused an uproar on social media, followed by condemnations by top Malaysian officials including the foreign minister.

"I am appalled by her horrendous statements," Singapore's foreign minister Vivian Balakrishnan tweeted last week.

"We treasure our ties with family and friends in Malaysia, and are sorry for the offense and hurt caused to all Malaysians."

Chia, however, has stood by her joke despite the intense backlash.

The US-born former lawyer told CNN that she had performed that set "more than a hundred times" for more than a year without problems.

"I do stand by my joke, but with some caveats I stand by it in its entirety when viewed in a comedy club," she told the broadcaster in comments published on Sunday.

She added, however: "Upon reflection I do see that having this as a clip that gets viewed out of a comedy club context was risky."

Chia was defiant even after Malaysia's move to involve the international police body, tweeting: "Would love to see the face of the Interpol officer who received this request."