Abbott said a deal to allow the police mission into the rebel-held territory was reached after discussions were held in Donetsk, Ukraine, under the auspices of the Organisation for Security and Co-operation in Europe.
"Today, I announce that the Australian Federal Police will be deployed to the site as part of an unarmed, Dutch-led international humanitarian mission," Abbott said at a press conference in Canberra today.
"Today, there should be 49 on site, of whom 11 will be Australian, and I expect there will be considerable more on site in coming days."
The prime minister stressed that while Australian Defence Force (ADF) personnel were part of the team his country had sent to Europe after the plane crash, the operation was "not a military one".
"Yes, there are some ADF enablers involved, yes there's always in circumstances like this a certain amount of contingency work, but this is a police mission, not a military one," he said.
Abbott said the operation's objective was "to get in, to get cracking and to get out", adding that "we will stay as long as we can to do a professional job but we won't stay a moment longer than we need to".
"This is a risky mission, no doubt about that. But all the professional advice I have is the safest way to conduct it is unarmed, as part of a police-led humanitarian mission."
Australia and the Netherlands had been readying their forces in Europe to secure the MH17 crash site, amid concerns the remains of some of the 298 passengers killed on board the Malaysia Airlines jet were yet to be recovered.
Abbott said although the rebels accused of shooting down MH17 with a missile from Russia have signalled they were only open to allowing a small group of officers in, the Donetsk deal had made it possible for more personnel to enter the debris site.
"As a result of the discussions in Donetsk overnight under the auspices of the OSCE, we are confident that we can put more numbers out and that we will be able to take over the site at least for the purposes of recovery of remains and to the extent necessary - investigation," the Australian leader said.
Abbott said while the contingent would not be allowed to stay at the crash site overnight, he was "confident over time that as trust builds up, more will be possible".