Kim Jong Nam, pictured in 2001, was the heir-apparent in North Korea until he was exiled in 2003 for criticising his family's regime.

North Korean dictator Kim Jong Un's half-brother reportedly had US$120,000 [NZ$166,000] in his possession when he was killed at a Kuala Lumpur airport in February.

Japan's Asahi newspaper, which ran the story, added that he met with an American suspected of connections with a US intelligence agency four days before his death.

Kim Jong Nam is believed to have met the US citizen for two hours at a hotel in Malaysia and picked up the money while in the country, the newspaper said, citing unnamed officials from the country's investigation authorities.

SUPPLIED Doan Thi Huong of Vietnam, left, and Siti Aisyah of Indonesia are accused of Kim Jong Nam's murder.

Asahi said Malaysian authorities believe he may have been paid for information, and there was no record of any such withdrawal from banks in the country.

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FUJI TV/AP Kim Jong-nam, in grey, gestures towards his face while talking to airport security shortly before his death.

The eldest son of late North Korean leader Kim Jong Il was killed at the airport by two women who swiped VX nerve agent on his face, according to Malaysian authorities. South Korean government officials have speculated that Kim Jong Un was behind the murder of his half-brother, a critic of his leadership who had lived outside the country for years.

Malaysian authorities found four bundles of US$100 bills tied together in stacks of 300 mostly new notes in his bag, the paper said. Kim Jong Nam held a diplomatic passport so his luggage wasn't subject to thorough searches when entering and leaving the country, Asahi said.