British newspaper The Sun reported that Iwobi was pictured and filmed dancing at a houseparty after 2.30am on Saturday before the Gunners were upset by the Championship side.
Iwobi played the full 90 minutes as Arsenal went down 4-2 to their hosts thanks to an Eric Lichaj double and second-half penalties from Ben Brereton and Kieran Dowell.
And Wenger has confirmed that the club will not accept such behaviour from one of their stars and will come down heavy on him if the allegations prove to be true.
“If that is true he will be fined. It’s unacceptable," he told reporters on Tuesday. “I will have to see him and see if that is right or not.
“If he was at a birthday party, how long has he stayed? That is very important. After that I will decide what happens.
“If your neighbour takes drugs, what can you do about it? You are responsible for your behaviour.
“You must have played football, you want to prepare 100% but sometimes it is not a guarantee that you will be at your best.
“But that is what is requested from a top professional.”
Iwobi has been in and out of the Arsenal first-team this season, starting 10 of his 11 Premier League appearances this term and scoring one goal.
“I would love to win it because we are now in the semi-final," he said. "If there’s an opportunity we will try to take it.
“There’s still a long way to go. It’s similar to what we saw last year in the FA Cup.”
Arsenal visit their London rivals for the first-leg before the return at the Emirates Stadium on January 24.