The Australian and Dutch governments remain determined to get access to the MH17 crash site despite setbacks due to continued fighting in the Ukraine.

Australian and Dutch police aren’t giving up hope of accessing the MH17 crash site despite fighting between Ukrainian forces and separatists in the country’s east.

Investigators were forced to abandon their mission for a fourth consecutive day on Wednesday because of clashes close to the site where the Malaysia Airlines plane was shot down, killing all 298 people on board including up to 39 Australian citizens and residents.

However, specialist equipment is still being flown in to the Ukraine ahead of a possible breakthrough.

Having been briefed on the latest turnback, Prime Minister Tony Abbott said investigators were not giving up hope.

“We will not readily be deterred here. We are determined,” Mr Abbott said.

Palmer United Party leader Clive Palmer is the first senior political figure to urge a pull-out.

“Time to bring our AFP team home from eastern Ukraine if they can’t get to #mh17 crash site as they will be harm’s way in hostile situation,” Mr Palmer said on Twitter.

Mr Abbott announced on Thursday that a national memorial service would be held in Melbourne on August 7.

The multi-faith event will be at St Patrick’s Cathedral.

The remains of up to 80 bodies are believed to still be at the crash site in the Donetsk region of eastern Ukraine where the plane went down on July 17.

Mr Abbott declined to blame Russia for frustrating the recovery effort despite Foreign Minister Julie Bishop earlier raising concerns about Moscow’s role in actively undermining the process.

“Whilst I can’t point the finger at who starts the shelling, we get absolute assurances from the Ukraine government that it’s not them,” Ms Bishop said.

She described as “utterly despicable” unconfirmed reports that Ukrainian rebels had been laying landmines on roads throughout the crash site.

Australian and Dutch aircraft have been flying equipment for the investigators into the Ukrainian city of Kharkiv for when they get the green light to proceed to the crash site.

Dutch officials said the investigative team wanted to examine the entire disaster area to salvage and recover all the victims and their personal belongings.

The Dutch Safety Board, which is analysing the flight recorders, is expected to publicly release an initial report within days.

There is also an criminal investigation under the leadership of Dutch government’s Public Prosecution Service.

Of the passengers, 193 were from the Netherlands, including at least 22 children.