Kim Jong Nam
Kim Jong-Nam, the eldest son of former North Korean leader Kim Jong-Il in 2010 JoongAng Sunday/AFP

The half-brother of North Korean dictator Kim Jong-un has been assassinated in Malaysia, according to reports.

South Korean news agency Yonhap and other media organisations are claiming that Kim Jong-nam has died, citing several government officials.

News channel TV Chosun said the 45-year-old was poisoned at Kuala Lumpur International Airport by two women, believed to have been North Korean operatives.

The females are said to have attacked Kim with "poisoned needles" before fleeing the scene.

A second report from Malaysian police said a man believed to be Kim died en route to a hospital after falling ill at the capital's airport.

Kim was the eldest son of late former leader Kim Jong-il but did not live in North Korea or hold any official title. He was born from his father's relationship with Sung Hae-rim, a South Korean-born actress who died in Moscow, reported Yonhap.

He was disowned by his late father after he was arrested in 2001 at Tokyo's Narita International Airport for travelling on a forged passport. He was said to have been attempting to visit Tokyo Disneyland.

After getting deported to China, Kim was reported to have spent several years living in Macau, where he was frequently spotted "dining and drinking in restaurants and gambling on slot machines," the South China Morning Post wrote in 2007.

The one-time heir apparent once told a Japanese newspaper he was in favour of reform in Korea and opposed his family's dictatorship and power transfers.

In 2012, author Yoji Gomi claimed he had spoken to Kim several times following the death of his father and he was reportedly not confident in his half-brother's abilities to take over as leader of the secretive state.

He said: "[Kim] sees his brother failing. He thinks [Kim Jong Un] has a lack of experience, he's too young, and he didn't have enough time to be groomed. Those three reasons are why he thinks he'll fail."

In December 2013, the North Korean government executed Jang Song-thaek, the uncle of Kim Jong-un, over allegations the then second most powerful man in North Korea was attempting to overthrow the country's leadership.

In a rare moment of transparency, the government issued a 2,700 statement explaining why they killed the "traitor" while describing him as "despicable human scum [who is] worse than a dog".