The attack killed a Bulgarian bus driver and five Israeli tourists. A large number of people were also injured in the attack which investigators said was carried out by a suicide bomber who was also killed in the attack.
European police however say the bombing was more likely triggered by remote-control.
Bulgarian government officials announced earlier this month that Hezbollah was believed to be behind the attack. Interior Minister, Tsvetan Tsvetanov, said at the time links with Lebanon had been uncovered.
Later however he said the two suspects under investigation were a Canadian and an Australia who had lived in Lebanon for a period prior to entering Bulgaria.
At the time of his announcement of Hezbollah's involvement, the Bulgarian interior minister said Bulgarian investigators had been assisted by Israeli and U.S. security services, and that crucial evidence had been provided by Israel. On Friday Tsvetanov issued a statement saying Canada and Australia also offered information indicating that Hezbollah funded the Burgas attack.
"What remains is to identify with Europol the transit of funds and bank transactions," he said.
Tsvetanov said the two accused have relatives in both Australia and Canada.
"They studied engineering in Lebanon and are 26 and 33 years old and have dual nationalities," he said.
While in Bulgaria the men were using the aliases of Ralph Rico and Brian Jensson.
News of Australia's involvement in the Burgas attack investigation coincides with news this week of another Australian, Ben Zygier, who allegedly hanged himself in a suicide-proof prison near Tel Aviv in 2010.
Like the suspected Australian in the Bulgarian attack, Zygier also operated with a number of aliases using false passports. He however is alleged to have been working for Israel's Mossad, not Hezbollah.