McCarthy, 28, Southampton's first choice despite competition from Fraser Forster and new arrival Angus Gunn, has replaced Burnley's Nick Pope in the England squad for the UEFA Nations League double-header against Spain and Croatia.
When asked if he could see McCarthy as England's No.1 one day, Hughes remarked: "I see no reason why he can't.
"His fundamentals are very sound. He's a big guy but very mobile and very dynamic in his box.
"He's a top level keeper and will push whoever is in possession of the shirt.
"I think he deserves it in where he was when he first came to the club and wasn't first choice but worked his way in by virtue of performances.
"He was instrumental at the back end of last year and made match defining saves to protect results and gain points.
The next thing is international recognition which he's got and everyone's really pleased for him."