Kim Jong Nam was killed at Kuala Lumpur International Airport on February 13 while he was preparing to board a flight to Macau, where he lived with his family under the protection of Beijing.
South Korean and US officials believe the killing was an assassination carried out by agents of the North to eliminate the elder half brother of North Korean leader Kim Jong Un.
Police chief Khalid Abu Bakar named the North Korean diplomat wanted for questioning as 44-year-old Hyon Kwang Song, and said he held the rank of second secretary at the embassy.
The police chief identified the Air Koryo staffer as Kim Uk Il, 37, and said another North Korean suspect wanted for questioning was Ri Ji U, but gave no further details.
He said all three were in Malaysia.
"They're not in custody, they've been called in for assistance," Khalid told reporters in a news conference.
Calls on Wednesday to the North Korean embassy for comment on the latest developments went unanswered.
Police have stepped up security at the morgue where Kim Jong Nam's body is being held after an attempted break-in earlier this week, Khalid said. Malaysia has denied North Korea's request for the body to be handed over to its embassy directly.
Malaysia has so far identified a total of eight North Koreans suspected of being linked to killing.
One is in custody, along with two women - one Vietnamese, one Indonesian - believed to have carried out the fatal assault using a fast-acting poison.
Khalid said police "strongly believed" four other North Koreans were back in the North Korean capital of Pyongyang, having fled Malaysia on the day of the attack.


