International probe teams, including from Malaysia, still cannot enter the Malaysia Airlines flight MH17 crash site in eastern Ukraine as it is still unsafe.

Home Minister Datuk Seri Ahmad Zahid Hamidi said this is despite the ceasefire agreement signed between the Ukrainian government and the separatists and monitored by the Organisation for Security and Cooperation in Europe (OSCE).

"Our probe team has to enter the crash site soon as the arrival of winter will make it difficult to find the evidence.

"What's more, it has been a long time since the crash and this will make their work more difficult," he told reporters after the ministry's monthly assembly here, Thursday.

Malaysia's probe team comprising of 30 police officers who left for Ukraine recently to continue the investigation are still stuck in Kiev.

Zahid said the probe team has at least 45 days to enter the crash site before an extreme winter falls on eastern Ukraine.

The collaboration with international forces from Netherlands and Australia will hopefully make the warring parties to allow the probe to continue.

The Ukrainian government has expressed support for the Malaysian probe team to return to the crash site to conduct an investigation.

Asked what if the probe team still failed to enter the crash site, Zahid said Plan B is to continue the investigation indoors.

"We will conduct analysis of evidence collected by the team earlier in Kiev and the Hague," he added.

MH17 carrying 298 passengers including crew from Amsterdam to Kuala Lumpur was believed shot down over eastern Ukraine on July 17.

A preliminary report by the Dutch Safety Board (DSB) said the MH17 aircraft broke up in mid-air after being hit by 'objects' at high velocity.

There were no indications that the crash was due to technical problems or by action of the crew and the aircraft was certified "fit to fly".