The remains of Callum, 33, and Jake Robinson, 30, and their American friend Carter Rhoad, 30, were found in a well earlier this week in what authorities are treating as a murder investigation.
Federal Treasurer Jim Chalmers said the brothers' bodies being identified was "frankly horrendous news".
"I think the whole country's heart goes out to all of their loved ones. It has been an absolutely horrendous, absolutely horrific ordeal and our thoughts are with all of them," he said.
Bodies found after a search by Mexican authorities have been identified by family members. (HANDOUT/SUPPLIED)
The Robinson brothers, originally from Perth, were travelling in northern Mexico on a surfing holiday when they failed to check into pre-arranged accommodation near the city of Ensenada.
WA Premier Roger Cook said the situation was incredibly sad for the brothers' family and friends.
Callum was a member of Australia's national lacrosse team and Lacrosse Australia said its thoughts were with the families of the Robinson brothers and their friend.
"Lacrosse Australia is deeply saddened by the deaths of player Callum Robinson, Callum's brother Jake Robinson and their friend Jack (Carter) Rhoad and send our deepest condolences to their families, friends and teammates," the association posted on Facebook.
About 150 people gathered for a vigil in San Diego where Callum attended university, the American ABC network reported.
The family had travelled to Baja California state in northern Mexico and were taken to view two bodies found at the bottom of a well.
The remains were found with a third body, and a corpse that had likely been there for some time, in the well on a cliff top on Baja Peninsula on Mexico's west coast early on Saturday, Australia time.
Baja California state prosecutors said relatives from the two countries had viewed the corpses recovered from a remote well about 15 metres deep and recognised them as their loved ones.
Thieves apparently killed the three, who were on a surfing trip to Mexico's Baja peninsula, to steal their truck because they wanted the tyres. They then allegedly got rid of the bodies by dumping them in a well near the coast.
The well was located some six kilometres from where they were killed.
Three suspects are being held in connection with the case, which locals said was solved far more quickly than the disappearances of thousands of Mexicans.
Baja California prosecutors confirmed last week they were questioning three people over the case.
Authorities said on Saturday a criminal charge of forced disappearance, equivalent to kidnapping, had been laid against one of the three.
Mexican authorities' preliminary hypothesis is that the suspects tried to carjack the trio and when the surfers resisted, they were shot and their bodies dumped in the well.
Investigators also found a burnt-out white ute, believed to be the vehicle in which the men were travelling when they disappeared.
A burnt-out ute was found near where the Robinson brothers and a US friend were camping. (HANDOUT/SUPPLIED)
The chief state prosecutor's office said evidence found along with abandoned tents at a burnt-out campsite was linked to the three people being questioned about the missing foreigners.
Local news outlet Zeta reported the fourth body found in the well was believed to be that of the property's owner, who had been missing for several weeks.
The Robinsons' mother Debra had appealed for help to find her sons and their US friend, saying she had not heard from them since Saturday.
"Callum is a type one diabetic so there is also a medical concern," she wrote on Mexican social media.
Both US and Australian authorities have urged people to exercise a high degree of caution when travelling to Baja California "due to the threat of violent crime".
with Reuters and AP
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