The Italy and Juventus shot-stopper spoke to the Mail on Sunday about the lack of confidence in Hart’s abilities.
“There is usually an order in which you do these things; you normally play for your club and then you play for your national team," he said.
“To try to play for your national team when you're not playing for your club will become a struggle in the end.
“A player such as Iker Casillas can do it because he has great experience of victory and incredible value as a goalkeeper. But they are very few, those who could succeed in playing for their national team while not playing for their club.
“As soon as he can start playing regularly again, in my opinion, he can go back to playing as well as he did before, if not better.”
Buffon admitted Hart should consider quitting Manchester City if manager Manuel Pellegrini continues to shun him in the crucial months leading up to the World Cup.
“These are personal choices. They depend on desire and aspiration. They depend on the aspirations of the player. And they depend on the desire of the player to bring his aspirations into the discussion.”
Italy play their opening World Cup game against England in Manaus on June 14, though the kick-off time was brought forward by FIFA under pressure from television companies.
It will now begin at 18.00 local time, 23.00 in the UK and midnight in Italy. Click here for the full World Cup schedule.
“We are competition animals. However we play in between tournaments, we always come good in the tournaments themselves,” added Buffon.
“It doesn't matter that we're not quite where we want to be right now, in terms of our recent form. You will see the best of Italy by the time we kick off at the World Cup.”