A five-nation "coalition of the grieving" is expected to supply the forces to secure the 50-square-kilometre crash site of Malaysian Airlines' downed MH17.
The multinational force is expected to be led by the Dutch, who lost 193 nationals in the bringing down of the plane, while Australia could serve in the deputy role.
Malaysia, Germany and Britain are the other three nations that are expected to contribute to the security force, with Malaysia having lost 43 people in the tragedy.
Security forces from the Netherlands and Australia worked closely together for years in Oruzgan province, Afghanistan.
Germany and Britain are said to be in discussions about the nature and composition of the forces they would look to send to the site, which lies deep in rebel-held territory in eastern Ukraine.
Foreign Minister Julie Bishop is in Ukraine and at 9.30am Australian EST time, signed an agreement with Foreign Minister Pavlo Klimkin that will provide a legal basis for Australia's presence in that country.
The arrangement will not come into effect until signed off by President Petro Poroshenko and passed by the Ukraine Parliament, which could take some time.
Once operating, it will allow Australian officials freedom of movement in the Ukraine, allow them to work with local authorities and allow equipment and supplies to brought into the country. It will also cover legal matters such as liability.
President Poroshenko confirmed in a statement that his nation planned to sign a joint agreement with the Australian government that would cover Australia participation in the mission to protect the international investigation.
Earlier, President Poroshenko, Dutch Foreign Minister Frans Timmermans and Ms Bishop also signed a Memorandum of Understanding on the investigation of MH17.
Under that MoU, the Ukraine delegated authority to Holland, as the nation that lost the majority of victims in the crash, to investigate the case.
''Countries whose citizens died in this terrible tragedy are scattered around the world. That's why we must be united to ensure co-ordination of actions in holding the efficient investigation and submitting its results to the world,'' the Head of State emphasised.
He thanked Australia and the Netherlands, ''with whom we are increasingly efficiently coordinating our actions and elaborating concrete mechanisms to ensure transparent and independent international investigation''.
The force is being put together in negotiation with the Organisation for Security and Cooperation in Europe (OSCE), which has people on the ground at the crash site.
Ten British citizens and four Germans were among the passengers on MH17. Britain's Prime Minister David Cameron has been sharply critical of Russia, telling Vladimir Putin in a phone call that the Russian President "must change course and work to bring stability to eastern Ukraine", according to a British spokesman.
German chancellor Angela Merkel has said that "Russia is responsible for what is happening in Ukraine at the moment".
Like the Netherlands, Britain and Germany are members of the NATO alliance with the US.
International officials have told Fairfax Media that the United States said that it was prepared to contribute if asked, but the Dutch and Australians have decided not to ask for an American contribution.
Prime Minister Tony Abbott announced on Thursday that 50 Australian federal police had been pre-deployed to London in expectation that they would be sent to the crash site as part of a force operating under UN authority.
It has not yet been decided whether the police would be armed or whether they would be accompanied by military forces to provide security.
However, Australia has been working to negotiate terms with Kiev, Moscow and also the self-declared government in Donetsk, so that it would be safe enough to deploy officers. Mr Abbott has also spoken with Ukrainian President Petro Poroshenko, who welcomed the announcement about the 50 AFP officers.
Mr Abbott said he "would be very careful about putting any Australian personnel into harm's way", but that the crash site had become more "permissive" in recent days, with European officials now able to visit the site.
In their most recent conversation, Mr Abbott said Mr Putin had said all the right things and confirmed the importance of securing the site..
"On the site, it is still clear that nothing is happening without the approval of the armed rebels,'' Mr Abbott added.
"President Putin gave me assurances that he wanted to see the families of the victims satisfied. He wanted to see, as a father himself, grieving families given closure. So far he has been as good as his word."
The Dutch newspaper De Telegraaf has flagged the possibility that members of that country's airborne brigade could be deployed alongside military police.
And Volksrant reported the Dutch government was "seriously considering" a group of soldiers and policemen, on condition the group is part of a multi-national force.
And overnight, news wire Agence France Presse reported that Dutch Prime Minister Mark Rutte said 40 unarmed Dutch police would be sent to the crash site to stabilise the area.
The agency quoted OSCE spokesman Michael Mociurkiw saying that an Australian federal police officer was reportedly "sussing the security and then possibly coming here" to the crash site in Ukraine.
At the same time, the European Union is stepping up sanctions on 15 Ukrainian and Russian individuals and 18 entities because of their role in the ongoing Ukraine crisis.
