The Australian government says it will demand a full, independent inquiry of the downing of flight MH17 in Ukraine.

Australian officials are trying to access the crash site in Ukraine where a Malaysia Airlines plane went down, ahead of a likely international investigation into the events that led to the disaster.

US President Barack Obama and Ukrainian President Petro Poroshenko have agreed in a telephone call on the need to prevent tampering with debris from the Boeing 777 jet that crashed in rebel-held eastern Ukraine after apparently being hit by a surface-to-air missile.

“The presidents emphasised that all evidence from the crash site must remain in place on the territory of Ukraine until international investigators are able to examine all aspects of the tragedy,” the White House said.

The statement raised the possibility that US officials are concerned pro-Russian forces could try to tamper with the evidence of the wrecked aircraft to cover up who is to blame.

Australian Foreign Affairs Minister Julie Bishop said Australian officials were seeking permission to access the crash site and would demand a full, independent international inquiry into the disaster.

“Regardless of the circumstances we urge the separatists to co-operate with an investigation into this crash,” Ms Bishop told reporters in Brisbane on Friday.

“If they have taken the black box, it must be returned to authorities immediately.”

Global air safety group, the Flight Safety Foundation, says coalition of countries must lead the inquiry rather than the country where the disaster happened, as would normally be the case.

The federal government on Friday convened an emergency meeting of the National Security Committee of cabinet to discuss its response to the crash, which has claimed the lives of at least 27 Australians.

“This incident underlines the urgent need to de-escalate tensions in eastern Ukraine,” Ms Bishop said.

Ms Bishop said the government was mobilising staff from across Europe to respond to the tragedy.

She also cautioned that now all the nationalities of those on board the plane had been determined “so the final number may be higher”.

Ms Bishop and Prime Minister Tony Abbott have already spoken with their counterparts in the Netherlands.

Australia is also sending officials to the Ukrainian capital of Kiev to provide assistance.