An Australian with connections to the Hezbollah militant group is one of the key suspects in a bombing that killed five Israelis and a local bus driver at an airport at a Black Sea resort last year, the Bulgarian Government announced overnight.

Releasing the results of its investigation into the July 18 bus bombing in the coastal town of Burgas, Bulgarian Interior Minister Tsvetan Tsvetanov said one of the suspects entered Bulgaria on an Australian passport, and another with one from Canada.

All three people involved in the attack had fake US drivers licenses that had been printed in Lebanon, while the two travelling on Australian and Canadian passports had lived in Lebanon since 2006 and 2010 respectively, the Agence France-Presse news agency quoted Mr Tsvetanov as saying.

“We have well-grounded reasons to suggest that the two were members of the militant wing of Hezbollah,” Mr Tsvetanov said. "There is data showing the financing and connection between Hezbollah and the two suspects.