The Associated Press news agency filed pictures from the town of Bint Jbeil showing the funeral procession.
Meanwhile, Reuters has cited security and other sources on the ground in Lebanon as saying all were killed in an Israeli airstrike that hit a home in the Al-Dawra neighbourhood.
Ahmad Bazzi, the father of Ibrahim and Ali, mourns over one of the coffins at a funeral procession. (AP PHOTO)
The dead have been identified by Middle Eastern media as Australian-Lebanese civilian Ibrahim Bazzi, his wife Shorouq Hammoud, a Lebanese citizen, and his brother Ali Bazzi.
"They were in their homes," a medic who works with the Civil Defence in south Lebanon told The National, the English-language United Arab Emirates-based news outlet.
He said there were no signs of fighting nearby before the strike and that Ms Hammoud was recovered first from the debris.
"When they found her she was alive, but she died shortly after," he told The National. This could not be independently confirmed.
Lebanon's National News Agency also reported the deaths, saying the home belonged to the Bazzi family.
Hezbollah, which has widespread support in the area, later announced Ali Bazzi as one of the Shi'ite Muslim group's fighters, Reuters said.
A fighter kisses the coffin of Ali Bazzi, who was killed with his brother and his brother's wife. (AP PHOTO)
Hezbollah, an ally of Palestinian Islamist faction Hamas, has been exchanging fire with Israel across Lebanon's southern frontier since the Israeli-Hamas war in Gaza began on October 7.
Asked about the incident, the Israeli military said one of its jets had struck a Hezbollah military site overnight in Lebanon, Reuters added.
Australia's Department of Foreign Affairs and Trade on Wednesday said it was aware of reports that an Australian had been killed in an airstrike in Lebanon and was seeking confirmation.
The coffins of Ibrahim and Ali Bazzi and Shorouk Hammoud. (AP PHOTO)
Ms Hammoud was recently granted an Australian visa. She and her husband, who have been married for three years, planned to travel soon to Sydney, Nine News reported.
Ibrahim Bazzi is believed to have moved to Australia in 2020-21.
Australia's Smartraveller website maintains a "do not travel" warning for Lebanon citing the possibility of increased armed conflict, as well as daily military action in the country's south including airstrikes.
with Reuters