The federal government is working to have plans in place in case the security situation in Lebanon deteriorates further but Australian citizens have been urged to heed warnings and leave immediately.
About 15,000 Australians live in Lebanon, according to Foreign Affairs Department estimates.
It may be impossible to leave in coming days and commercial flights out of Beirut may be stopped, Prime Minister Anthony Albanese has warned.
"Given the numbers of people who are there, there's no guarantee ... people will be able to come home through other means if that airport is shut," he told reporters in Sydney.
The warning follows an Israeli drone strike that killed Hamas leader Ismail Haniyeh, sparking fears of retaliation.
Defence Minister Richard Marles said the government was "thinking through contingencies" but didn't go into further detail.
"But we have a significant population of Australians who are in Lebanon, and if you are seeking to leave, you should be doing so right now," he told reporters in Darwin.
The Australia Defence Force most recently helped evacuate citizens from deadly riots in New Caledonia in May.
It has also helped evacuate Australians and their families from Israel on a KC-30A and a C-17A Globemaster following Hamas' October 7 attack.
Foreign Minister Penny Wong also ramped up warnings to leave in a video message.
"My message to Australian citizens and residents in Lebanon is now is the time to leave," Senator Wong said in the video posted on social media.
"You may not be able to leave Lebanon for an extended period."
Australians in Lebanon have been advised to register their details with the Department of Foreign Affairs.
Mr Albanese repeated calls for a stop to the conflict and for a ceasefire.
"We want to see the hostages released, and we want to see a plan for peace and security in the Middle East," he said.
Israel had acted in self-defence in relation to the death of Hamas' leader, Opposition Leader Peter Dutton said, adding retaliation was expected "given the slaughter that took place on October 7".
"We know with Al-Qaeda and other terrorist organisations, they pose a threat to our way of life," he told Sky News.
"They certainly pose an existential threat to the Israeli people."
The potential escalation of conflict also prompted warnings the humanitarian situation in the Middle East could worsen further.
Advisor for the Australian Council for International Development Naomi Brooks said further tensions would stretch already limited resources and civilians would pay the price.
"The ability for humanitarian assistance to be provided remains extremely difficult, and long-standing norms of international humanitarian law continue to be eroded," she said.
A similar situation in a 2006 war between Israel and Hezbollah forced the evacuation of some 5100 Australians from Lebanon.
Depart of Foreign Affairs deputy secretary Craig Maclachlan expressed concern in October that Australians were not heeding a similar message to leave.
