The 20-year-old Groningen bolter is understood to be the biggest surprise to be announced in the extended 30-man squad for the upcoming World Cup qualifier against Saudi Arabia, friendly against Brazil and Confederations Cup in Russia in what will be one of the biggest months for the national team in recent years.

Should Hrustic be announced by coach Ange Postecoglou on Monday, it will represent a major coup for Football Federation Australia, whose staff have worked extensively to secure the services of the Melbourne-born winger who has also been chased by his father's native country, Bosnia and Herzegovina.

Hrustic left Australia at a young age to pursue his footballing career in Europe, moving to Austria Vienna in 2012, before joining German Bundesliga giants Schalke, then Dutch club Groningen.

He had been firmly off the radar for Australian youth teams, having never represented his country of birth in any age group below the senior team. His availability prompted Bosnia and Herzegovina to make approaches to include Hrustic in their Under-21 squad for their upcoming Euro qualifier against Switzerland. However, Hrustic's allegiance will be locked in for Australia should he step on the field against Saudi Arabia or in the Confederations Cup in Russia. He could still be eligible to represent his ancestral country if he plays against Brazil as it is a friendly game.

The gain of Hrustic is another feather in the cap for Postecoglou who has been on a mission to bring in as many players with dual nationality as possible, to stop the drain of eligible Australians playing for other countries. Australia's coach successfully brought in Brad Smith (England), Apostolos Giannou (Greece), Milos Degenek (Serbia), Chris Ikonomidis (Greece), Jamie Maclaren and Jackson Irvine (both Scotland) while, at youth level, former Italian Under-17 international Reno Piscopo switched to Australia.

Meanwhile, Tim Cahill 's place in the squad is set to continue for the June series, with the veteran forward understood to be one of the likely names read out at Monday's announcement. The 37-year-old Melbourne City forward came under criticism from Postecoglou due to his lack of regular game time back in March, but having regained a starting spot late in the season he appears to have secured a place in the 30-man squad.

Mustafa Amini made his debut for Australia in their last game, a 2-0 win over UAE at home, and is another likely to keep his place in the extended squad. Amini is locked in a relegation battle with his Danish club, Aarhus.

Sydney FC duo Rhyan Grant and goalkeeper Danny Vukovic are both likely to retain their places in the preliminary squad after earning their first call-ups for the March game against the UAE.

The 30-man preliminary squad will be trimmed later to 23 players ahead of the Saudi Arabia World Cup qualifier in Adelaide.