PARLIAMENT The government could not take action against suspected North Korean operatives in Malaysia prior to the Kim Jong-nam murder as they had not committed a crime, said Deputy Home Minister Nur Jazlan Mohamed.

Nur Jazlan said the authorities were aware of the spies, but that they could not make such knowledge public as it is a "government secret."

"We know if there are spies, but there is no need to trumpet it.

"If police did not know (about the spies),how could they issue an Interpol red notice for these people," Nur Jazlan said.

However, Mahfuz Omar (PAS-Pokok Sena) said this action was only taken after Jong-nam was killed, and that something should have been done prior to the incident.

To this, Nur Jazlan replied: "How can we make an arrest if they haven't committed a crime?"

Espionage is a crime according to Section 124M of the Penal Code, which is punishable with life imprisonment.

Section 124N of the Penal Code also states that attempt to carry out espionage is also a crime, punishable with up to 15 years in jail.

Asked to clarify his response, Nur Jazlan said that replied that evidence is required before action can be taken against suspected spies.

"You have to get evidence of their activities first. Good spies don't get caught.

"We don't have enough experienced staff to monitor all of them," he told Malaysiakini.

He added if there is enough evidence, action would have been taken behind the scenes as it involved foreign nationals.

Jong-nam - the half brother of North Korean leader Kim Jong-un - was killed in Malaysia on Feb 13.

Two women, an Indonesian and a Vietnamese, have been charged over the murder.

However, the charge sheet says that four others are wanted for the murder.

The four are believed to be North Korean nationals, who were present at the airport when Jong-nam was attacked with the nerve agent VX.

Police had obtained an Interpol red notice against the four.

An Interpol red notice acts as an arrest warrant for persons wanted for extradition.

The four suspects had left Malaysia immediately after Jong-nam was poisoned.