Speaking to reporters, Malaysian Inspector-General of Police Khalid Abu Bakar said police had also formally requested an interview with the North Korean embassy's second secretary, who is wanted for questioning.
Kim, the half brother of North Korean leader Kim Jong Un, died last Monday after a suspected poisoning
while on his way to catch a flight to the Chinese territory of Macau from Kuala Lumpur.
North Korea has furiously denied any involvement in Kim's death, publishing a strongly-worded article on Thursday in the country's state media, KCNA.
It quoted a spokesman for the Korean Jurists Committee who said responsibility for Kim's death lay with Malaysia, as he had died on their territory, and criticized the investigation.
"If you look at Malaysian police's investigation from crime investigation perspective and legal perspective, everything is full of weak points and contradictions," it said.
Embassy official, airline employee sought
Interpol notices are issued to police in 190 different countries to help track fugitives and share information about wanted criminals.
Malaysian police have previously said the four suspects who are the subject of the alert are believed to be back in Pyongyang.
In addition to the four suspects, three North Koreans are wanted for questioning
by Malaysian police, including Hyong Kwang Song, the 44-year-old second secretary at the North Korean embassy in Malaysia, and Kim Uk Il, an Air Koryo staff member.
Both are believed to still be in Malaysia.
Bakar said the North Korean embassy wouldn't be searched as they had diplomatic immunity.
Suspects 'trained for murder'
Indonesian Siti Aishah and Vietnamese woman Doan Thi Huong have already been taken into custody in connection with the alleged murder.
Bakar said at a press conference Wednesday the two women were trained to wipe a liquid substance on Kim's face, then immediately wash their hands.
He dismissed their earlier claims that they believed they had been on a prank show. "They knew it was toxic. Of course they knew," Bakar said.
Aishah's boyfriend, Muhammad Farid Bin Jalaluddin, who was taken in for questioning, was released on bond on Wednesday.
Poison reports false: North Korea
Diplomatic ties between North Korea and Malaysia are growing increasingly frayed
as the rogue state continues to condemn Malaysia's handling of the investigation.
Malaysian Prime Minister recalled his ambassador from Pyongyang after the North Korean ambassador accused their country of conspiring with "hostile forces."
In the article published on KCNA, North Korea accused South Korean conservative media of publishing a "false report" that Kim had been poisoned.
The article also fiercely rebuked Malaysia for its continued refusal to hand over Kim's body without DNA from a next of kin.
"This proves that the Malaysian side is going to politicize the transfer of the body in utter disregard of international law and morality and thus attain a sinister purpose," Thursday's article said.