Pyongyang has expressed distrust over the investigations carried out by the Malaysian police on the death of Kim Jong-nam.

"It has been seven days since the incident, but there is no clear evidence on the cause of death and at the moment, we cannot trust the investigations by the Malaysian police even though, it would be obtained.

"It only increases the doubts that there could be someone else's hand behind the investigations," North Korean ambassador Kang Chol told a press conference at the embassy in Kuala Lumpur this afternoon.

He accused the police of conducting the probe to achieve their political aim.

"We have been respecting the Malaysian police and waited with patience for their fair and accurate investigation result. On the contrary, they pinned the suspicion on us.

"The DPRK, a sovereign country and of the victim, cannot tolerate any false propaganda or criticism against it," Kang said.

Hence, he demanded that a joint investigation be conducted between Malaysia and North Korea over the death of Jong-nam.

If Malaysia agrees to the request, Kang added, North Korea will send their legal delegation here.

He also requested to meet the female suspects arrested over the case.

Kang further alleged that the authorities and Deputy Prime Minister Ahmad Zahid Hamidi have been issuing contradictory remarks over the matter.

He was referring to Zahid confirming another identity of Jong-nam, asking "How could the deputy prime minister have made a false remark one day before (our statement)?"

Kang also accused Malaysia of collaborating with South Korea to help create a distraction for the ongoing crisis surrounding South Korea's leadership.

At no point did Kang refer to the deceased as Kim Jong-nam, the half brother of North Korean leader Kim Jong-un, instead referring to him as Kim Chol as stated on the deceased's passport.

The murder of Jong-nam on Feb 13 has sparked diplomatic row between the two countries, after Kang accused Malaysia of colluding with "hostile forces". He was upset a post-mortem was conducted without North Korea's permission.

Wisma Putra summoned Kang today and the latter held a press conference outside the embassy to disclose "Malaysia's unjust behaviour and contradiction" regarding the case.

Kang only responded to the journalists who spoke in Korean and did not answer questions from the English speaking reporters.

Police have thus far arrested a Vietnamese woman, an Indonesian woman, a Malaysian man and a North Korean man in connection with the murder. They were seeking four more North Korean suspects in relation to the killing.

The cops urged Jong-nam's next-of-kin to come forward and identify the body latest by Feb 27.

"The Malaysian government has been transparent. The embassy has been kept informed of developments related to the matter as well as the processes involved under Malaysian law," said Wisma Putra.

Wisma Putra also noted that Kang met with deputy secretary-general for bilateral affairs, ambassador Raja Nushirwan Zainal Abidin.