North Korean leader Kim Jong-un's brother has been assassinated in Malaysia, South Korean media reports.

Kim Jong-nam was killed at Kuala Lumpur airport after being attacked by two women with "poisoned needles," according to local TV reports.

The two women, believed to be North Korean agents, escaped in a taxi, TV Chosun reported.

Yonhap News, citing a South Korean government source, also reported Mr Kim had been killed.

Malaysian police told Reuters an unidentified North Korean man died en route to hospital from a Kuala Lumpur airport.

The police said the man's identity had not been verified.

​Mr Kim went into hiding in Malaysia after the execution in December 2013 of his uncle, Jang Song-thaek, the once-powerful uncle of the current leader.

The eldest son of Kim Jong-il, he survived an assassination attempt in Macau in 2011.

While he was widely seen as heir to the hermit kingdom's throne, he fell out of favour after being detained while trying to enter Japan on a forged passport along with two women and a child.

He said he wanted to visit Disneyland.

If confirmed, Kim's case would mark the most high-profile death under the Kim Jong-un regime since the execution of Jang Song-thaek.

Kim Jong-nam was born from his father's non-marital relationship with Sung Hae-rim, a South Korean-born actress who died in Moscow.