Dean Lucas and Adam Coleman, both 33, had been missing for over a week when a van was discovered in the state of Sinaloa -- an area known as the home of the Sinaloa drug cartel.
The men, from near Perth in Western Australia, had been on a surfing trip from Canada to Mexico and were due to arrive in the city of Guadalajara on November 21, but they never showed up.
Foreign Minister Julie Bishop said Tuesday that the Australian government has "very grave concerns for their fate."
"Our consular staff have been working around the clock to determine their whereabouts," she said in an interview with Nine Network's Today show. "A vehicle registered in the name of one of the Western Australian men has been located. There are human remains and these are yet to be formally identified.
"We are working closely with the family, keeping the family informed of whatever we know and I understand that family members, a partner, will be traveling to the United States and then to Mexico to help with the identification."
According to the Australian Broadcasting Corporation (ABC)
citing Sinaloa state's attorney general, a Chevy van was found burnt beyond recognition on a back road in remote farmlands. It said DNA from what's believed to be two bodies will be sent to Mexico's national forensics laboratory to speed up the investigation.
The girlfriend of Coleman, Andrea Gomez, was also reportedly due to meet the surfers in Guadalajara.
Josie Cox, the girlfriend of Lucas, posted on her Facebook page that she has flown to Mexico to identify the bodies in the van. She revealed that Lucas had been set to propose.
Coleman's mother, Zena Cattermole
, also shared on her Facebook page that her "son's life has left us."
A GoFundMe page
has crowdsourced over $38,000 (U.S. $27,000) to help the families of the men in their journey to Mexico.
Authorities are trying to piece together the last movements of the two men. The ABC reported that Mexico's attorney general Arely Gomez Gonzalez had said they had caught the ferry from Baja California to Topolobampo, a port in northwestern Sinaloa, on Friday, November 20.