Not entirely unrelated to the influx of Palestinian refugees post-1948. The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), a UN agency that supports the relief and human development of Palestinian refugees counted counted 475,075 registered Palestine refugees as of 1 Jan 2019. By law, they are not entitled to Lebanese citizenship, social welfare etc, but in practice it doesn't work out that way.
During the civil war a wave of about 30,000 Lebanese migrated to Australia.
Contrary to the usual shit-stirrers like Lauren Southern, most of them have assimilated quite nicely even though a recognizably Lebanese community remains visible in the Canterbury-Bankstown area. As far as Sydney is concerned this is no different than the clearly noticeable Greek community* in Marrickville, Italian in Leichhardt, Vietnamese in Cabramatta, Korean in Campsie and so on. When the racist fucks among us drive through any of those areas they play a game called "Spot the Aussie". I doubt we'll ever be rid of them.Most immigrants were Muslim Lebanese from deprived rural areas who learned of Australia's Lebanon Concession and decided to seek a better life. They were Sunnis from northern Lebanon and Shias from southern Lebanon as Christian and Muslim Lebanese were unwilling to leave the capital city, Beirut. (Link)
Lebanon really had a diaspora of sorts. The population of Lebanon itself was 6.9 million in 2018. Another 8–14 million Lebanese are strewn all over the planet. (Ibid)
*JimC may be able to confirm or correct me on this: The largest metropolitan Greek population outside Athens is Melbourne.
