Prime Minister Tony Abbott has urged Australians to brace for painful and difficult weeks ahead following the downing of Malaysia Airlines flight MH17.

Prime Minister Tony Abbott says Australia should brace themselves for painful weeks ahead as world leaders push for an independent investigation of the downing of Malaysia Airlines flight MH17.

Mr Abbott said his thoughts were with the families of the 28 Australian victims who were among the almost 300 people on board flight MH17 when it was shot down over eastern Ukraine.

“Yesterday we saw the smouldering wreckage on our screens, today we have seen some of the faces of the dead,” he told reporters on Saturday.

“I don’t believe any Australian, any human being, could fail to be moved by what we’ve seen.

“I have to say that as a nation we need to prepare ourselves for difficult and painful weeks ahead as we strive to find out precisely what has happened and who was responsible.”

Mr Abbott said the priority was for an independent investigation into the crash and for experts to gain access to the site where MH17 came down in a rebel-held area near the Russian boarder in eastern Ukraine.

“Right now for all we know because this site is controlled by Russian-backed rebels, right now for all we know bodies remain strewn over the fields of the eastern Ukraine and armed rebels are trampling the site,” he said.

“So it is absolutely vital that an independent, international investigation begin as a soon as possible so that we can identify and recover the remains of all the Australians on board.”

Mr Abbott said he had spoken with several heads of state since the disaster, including US President Barack Obama.

All had expressed shock and indignation at what had happened and were determined that an independent investigation be carried out, he said.

Mr Abbott said a monitoring mission for the Organisation for Security and Co-operation in Europe did gain temporary access to the site of the crash overnight, but was driven off by gunfire.

“Presumably from the Russian-backed rebels,” he said.

“This does highlight, though, the difficulty and the danger of this situation.”

Foreign Minister Julie Bishop will be heading to the US to champion Australia’s campaign at the UN Security Council for an independent comprehensive international investigation with access to the site, debris, black box and any possible witnesses.

The Department of Foreign Affairs and Trade have deployed six officers to Kiev and more are on their way, including a five-member emergency response team, the prime minister said.

Australian Federal Police investigators are also on their way, and more are ready to be deployed as the situation develops.

Contingency arrangements have been put in place to repatriate the bodies, he added.

“Although I must caution this is likely to be weeks, rather than days ahead.”

Australia will do whatever it can to ensure the incident was thoroughly investigated and the perpetrators brought to justice.

Ms Bishop said she had been reaching out to her foreign minister counterparts.

The Ukraine government had said it would give Australia all the support it needed to access the site to retrieve bodies and protect evidence.

Australia’s calls for a binding resolution for a UN-backed, independent, impartial, investigation into the incident would be debated at the United Nations in New York next week.

Ms Bishop noted that for the investigation to proceed, a cease fire around the crash site would be required.

From New York she will head to Washington to meet intelligence experts to ensure Australia was fully briefed.

DFAT was in contact with the victims’ families, who don’t want the names of their loved ones to be officially released, although Ms Bishop recognised some family members had already gone public by speaking to the media.

When the time came, the government would support families who wanted to travel to the crash site and Ms Bishop said she had already spoken to Qantas and Virgin Australia about this.

Ms Bishop also said she had been trying to contact the Russian foreign minister.

Mr Abbott said he would be meeting Russia’s trade minister, who’s in Sydney for a G20-related trade ministers gathering, on Saturday to convey Australia’s position on the shooting down of the plane and other concerns.

“It’s clear that all the evidence at this stage suggests the aircraft was shot down,” he said.

Australia is very concerned about the crash site being contaminated by local militia or other people in the area.

Mr Abbott said Foreign Minister Julie Bishop had been unsuccessful in contacting her Russian counterpart so far.

But later on Saturday the prime minister will convey Australia’s concerns directly to Russian trade minister Alexey Ulyukaev, who is in Sydney for the G20 trade ministers’ conference.

Mr Abbott has not spoken to Russian President Vladimir Putin since the plane was shot down.

He also defended comments he made about suspected Russian involvement in the disaster, saying they were “very much in line” with a statement by US President Barack Obama.

He repeated that all the evidence at hand suggested that the aircraft was shot down from territory controlled by Russian-backed separatists, most likely with weaponry supplied by the Russians.

“Australia takes a very dim view of countries which facilitate the killing of Australians, as you’d expect.

“The idea that Russia can wash its hands of responsibility because this happened in Ukrainian air space just does not stand serious scrutiny.”

As president of the G20 this year, Australia could refuse to invite Mr Putin to the final meeting of the international forum in Brisbane in November.

Mr Abbott said Australia would wait and see Russia’s next moves before making its decision.

“Australia is a self respecting country,” he said.

“We want to ensure that visitors to this country have goodwill to this country. Visitors to this country are people who have done the right thing by this country.

Ms Bishop said Australia and other countries wanted the United Nations Security Council to provide a binding resolution for an independent investigation into the disaster.

However they would not wait for a resolution before beginning preparations for an investigation.

“Our first priority is to ensure that the site is secured and that the investigation can commence and to also ensure that those who have expertise in identifying and repatriating bodies have unfettered access to the site,” she said.

“So we will not be waiting for a UN Security Council resolution, but we will be pursuing one as soon as possible.”

Ms Bishop said countries including Australia hoped the UN would give the go-ahead for the International Civil Aviation Organisation to lead the investigation.