Arzani was left out of the Socceroos' recent friendlies against Norway and Colombia but fans will be delighted the Young Footballer of the Year was included in van Marwijk’s 32-player preliminary squad for the 2018 World Cup.

The Dutch coach said any debate about whether Arzani will play for Australia or Iran should be over after the teenager was selected for the Socceroos.

“Nobody has told me not to nominate him because of this,” he said.  “I think, and I hope that because we are nominating him that he will play for Australia.”

While Arzani is inexperienced at international level, van Marwijk admitted he could be the Aussies' X factor in Russia

“He only just turned 19-years-old, so he has to learn but I like players who can make a difference,” he said.

“Maybe a World Championship is too early for him, but I will not hesitate (if) I think that he can mean something for us.

“If he can make a difference in the last 10 or 15 minutes then I will not hesitate to nominate him, so, I am happy he is in the squad now.”

The Dutchman said Arzani’s recent consistent performances for Melbourne City in the A-League is the reason why the teenager was selected.

“Before March he didn’t play every week, he only played a few games,” he said.

“Now I have a lot of information. I have members of the technical squad watching players from all over the world and we also have a man here in Australia watching players.

“But about Arzani, I also have extra information. I also spoke with coaches he has worked with and as I said he has a lot to learn but he is a player that can make a difference.”

Sometime next week van Marwijk will reduce the preliminary squad from 32 to 26 players before the Socceroos arrive in Turkey for the start of their pre-tournament training camp from Saturday, May 19. 

Then, after the Socceroos play the Czech Republic in St. Polten, Austria on Friday, June 1 (local time), the final list of 23-players is scheduled to be announced in Turkey on Sunday June 3.

The Dutchman admitted that he already has an idea of who he plans to take to Russia.

“I should be lying but, in my head, there are 26/27 who are definite, but I should lie,” he said.

“Every coach has the same feeling and there are players who you are doubting a little bit but for me there are also a lot of players I’m sure about.”