The US is quietly reviewing its long-running mission in the Sinai, with the prospect that withdrawal would end Australia's 33-year involvement on the Egypt-Israel border.
Twenty-five Australian troops and the same number of New Zealanders now serve with the Multinational Force and Observers (MFO), a non-UN peacekeeping mission founded in 1981 to oversee the agreement that ended conflict between Israel and Egypt.
MFO is commanded by the US and has about 1650 personnel, mostly US soldiers but with significant contingents from Fiji and Colombia.
Last week the US revealed it was reviewing the future of Taskforce Sinai.
"The US is concerned over deteriorating security conditions in an area of northeastern Sinai, where Egyptian security forces as well as civilian and military elements of the MFO, including the US military forces stationed at the MFO North Camp, are exposed to potential risk," US State Department spokesman Mark Toner said.
American intelligence group Stratfor said, realistically, the US could either increase the size and capability of its force in the Sinai or withdraw it entirely.
If the US contingent withdrew, the MFO would inevitably disband, Stratfor said in an analysis released on Monday.
Australia has been involved in MFO almost continuously since 1982, initially with a larger contingent of 100 personnel with eight helicopters.
Australia's 25 soldiers serve in the MFO headquarters in what the Australian Defence Force calls Operation Mazurka.
This was once a low-risk mission but that's no longer the case because of the rise of militant Islamist groups in the Sinai.
In September 2012, dozens of gunmen - described as Bedouin jihadists possibly affiliated with al-Qaeda - broke through the security fence into MFO's North Camp, in the northern Sinai. Australians were on the base at the time but none were hurt.
Australia subsequently agreed to provide $1.5 million to improve force protection.
The security situation has deteriorated, with MFO personnel now travelling outside their bases in armoured vehicles.
In the 2014 annual report MFO director-general David Satterfield said his personnel risked being caught in crossfire between Egyptian forces and militants, or risked being deliberately targeted by militants.
