Carew has been heavily fined by O'Neill after being spotted in a Birmingham club in the early hours before the UEFA Cup meeting with Ajax last Thursday.
O'Neill said: "I have a perfectly good relationship with John Carew. I don't think I would be guest of honour if any of the players were asking people to go out and eat with them.
"But I have absolutely no problem with John. He stepped out of line, I dealt with it. It's over. There is not a problem. My relationship with John, I should imagine, wouldn't really change.
"I've been fined as a player myself and it didn't really change things. You might sulk for a day or two - or in my case for a month or two! But there is not a problem with John.
"If you talk about the way John reacted, he came on as a sub at Wigan and within 12 minutes had made a goal and scored one - not a bad way to resolve the situation, so I am really pleased.
"The crowd reaction to him was also very positive. It was great. Whether we would all have had a different reaction to everything had Wigan turned us over, who knows."
O'Neill also insisted Carew had not been dropped as a disciplinary measure for the Ajax encounter.
He said: "I knew nothing about the incident (with Carew) until after the Ajax game. He was rested for the game - as he has been for certain other midweek games."