Prime Minister Najib Abdul Razak tonight announced that the nine Malaysian diplomats and their families barred from leaving North Korea have finally been allowed home.

"Alhamdulillah, they took off from Pyongyang today at 7.45pm Malaysian time, and will land in Kuala Lumpur tomorrow around 5am," he said in a statement tonight.

Najib said that Malaysia will now allow all North Korean citizens to leave the country.

"In addition, following the completion of the autopsy on the deceased and receipt of a letter from his family requesting the remains be returned to North Korea, the coroner has approved the release of the body," he said.

Najib thanked those involved in the negotiations, which was led by the Foreign Ministry.

"I have a deep personal concern about this matter, and we worked intensively behind the scenes to achieve this successful outcome.

"Many challenges were overcome to ensure the return of our fellow Malaysians. The safety and security of our citizens will always be my first priority," he said.

Najib said he was also grateful to all Malaysians for being united in overcoming the crisis.

"It shows what can be achieved for the nation if we work together as one," he said.

The diplomatic relations between Malaysia and North Korea had deteriorated rapidly following the assassination of Jong-nam at Kuala Lumpur International Airport 2 on Feb 13.

Malaysian police concluded that the estranged half-brother of North Korean leader Kim Jong-un was poisoned using the chemical weapon VX agent.

Najib said his government believed strongly in the principles of justice and sovereignty.

"Our police investigation into this serious crime on Malaysian soil will continue.

"I have instructed for all possible measures to be taken to bring those responsible for this murder to justice," he said.

In the course of the investigation, North Korean ambassador to Malaysia Kang Chol repeatedly accused Malaysia of trying to frame his country for the murder.

Wisma Putra announced Kang Chol's expulsion from the country on March 4 and North Korea retaliated by refusing to allowing 11 Malaysians in Pyongyang from leaving the country.

However, two Malaysians were allowed to leave as they held United Nations' travel documents.

Malaysia subsequently imposed similar conditions on North Korean citizens.

A Vietnamese and Indonesian have been charged for Jong-nam's murder.

However, police believe that four North Korean citizens, who were the main suspects, had fled the country.