O'Neill has urged McClean to keep a low profile after he received death threats.
He said: "It didn't exist in my time but it is something that has cropped up now, the possibility of playing for either side - and that's something that James has done.
"He has been twittering and he has been doing that for some time. He has been given advice in closing the account down, so at least that's gone.
"He is going to get some sort of a reaction to it from somewhere but I am not so sure he should be reacting to the reactions.
"Whether it's the end of it or not (I don't know) ...but at least the Twitter account has gone."