In an interview with the UTV, the former England international - who is in Belfast to earn his coaching badges - said the rules on declaring should change because it's becoming a problem.
Barton explained: "I think a young player maybe at 11, 12, 13, if you declare for say Northern Ireland, then you get a lot of coaching from the IFA and they put a lot of time into you, then at 19 or 20 you decide you want to play for England or southern Ireland, is that fair?
"Well, if you said at 14 you want to play for England or southern Ireland then they could put the time into coaching you because that's where you're going to end up.
"But you're taking away from someone who doesn't have an option and might have been a kid who was maybe not as good at 13, but with the right coaching could have represented their country, so I think it's really unfair."
Maybe there could be a rule made where if you're a certain age you declare and that's it and that would stop it because it's becoming a problem now.
A controversial FIFA ruling exists that allows players born in Northern Ireland to declare for the Republic, regardless of blood ties, and a handful of players have taken advantage of it - despite spending time in the Irish Football Association's youth set-up.
The likes of James McClean, Dan Devine, Shane Duffy, Daniel Kearns and Paul George have all accepted age-group calls for NI, only to pledge their senior future to the FAI.
More recently 19-year-old Wolves striker Liam McAlinden revealed he is making the switch after representing NI at youth level.
Joey Barton continued: "It's unfair, isn't it? That's how I would see it to be. I've always been a great believer of you make your bed and you lie in it."
Barton, who started his career as a youth at Everton and has since played for the likes of Newcastle and Manchester City, also spoke about the infamous French accent he adopted in Marseille.
"You don't realise you're doing it at the time, then all of a sudden you realise and you know you look stupid," he said.
"I'd be quick to laugh at someone else if they did the same and, in the scheme of things, it was funny - but I'm not the first and I certainly won't be the last."