The body of Kim Jong-nam has been preserved to prevent deterioration, Deputy Prime Minister Ahmad Zahid Hamidi said today.

Jong-nam, the half brother of North Korean supreme leader Kim Jong-un, was murdered at KLIA2 on Feb 13.

"Yes, we have preserved the body as it is kept in the morgue and there has been fear of decay," Zahid told reporters at the Parliament lobby today.

He said the preservation process was not conducted at Hospital Kuala Lumpur, where the body is now kept.

The authorities will not release the body to North Korea until it can be conclusively identified as that of Jong-nam.

North Korea has cast doubt on the Malaysian investigation into the death, straining diplomatic ties between the two nations.

Two women, an Indonesian and a Vietnamese, have been been charged with murdering Jong-nam.

Police say two more suspects want for investigation into the murder, an Air Koryo staff and a diplomat, are holed up in the North Korean embassy in Kuala Lumpur.

Police cannot conduct a raid on the embassy as the Vienna Convention dictates that embassies are sovereign territories.