The alarm was raised when Callum and Jake Robinson, both in their 30s, didn’t check in to their accommodation.
Their mother Debra Robinson has appealed for help to find her sons on Mexican social media, saying she had not heard from them since Saturday.
“They are travelling with another friend an American citizen,” she wrote.
“They were due to book into an Airbnb in Rosarito after their camping weekend but they did not show up.”
The brothers were also travelling with an American citizen, who has also been reported missing.
Mexican police said they had arrested a woman and two men, with the woman being found with a mobile phone that contained a photo that looked like one of the missing brothers.
Prime Minister Anthony Albanese said Department of Foreign Affairs and Trade officials had been in contact with the family following the disappearance.
“This is a really concerning situation,” he said.
“Our embassy in Mexico is working with local authorities as well to try to ascertain what has happened here.
“We certainly hope that these brothers are found safely but there is real concern about the fact that they’ve gone missing. Their mother is obviously very distressed about this and we just hope for a positive outcome.”
DFAT also confirmed it was helping the family.
“Owing to our privacy obligations we are unable to provide further comment,” a spokesperson said.
– AAP