Ruddy was selected in Roy Hodgson's squad for the matches against Moldova next Friday and Ukraine the following Tuesday, along with Hart and Celtic's uncapped Fraser Forster.
Hodgson has backed Hart despite the goalkeeper being blamed for his part in Manchester City's shock 3-2 defeat by Cardiff on Sunday and being at fault for the first goal as England beat Scotland 3-2 earlier this month.
Hughton, however, insists Ruddy, who missed a large chunk of last season when he underwent an operation on a thigh injury, is in the sort of form to put real pressure on Hart.
Hughton said: "Any player that goes on international duty is there on merit and to challenge and to play.
"If I look at the progress he (Ruddy) has made over the last few seasons he has the capabilities to really push for a place.
"It's early in the season but if I look at the reaction from a disappointing season for him last season, at least the last two thirds of the season with the injury, he has made a full recovery from that and at the moment is back to where he was before the injury.
"I think he has done well and has put himself in position to put pressure on the position. And that's how it should be. Anyone who is involved in an international squad should be there on merit and feel they can put real competition on that position.
"He's a big personality, a big frame, and his performances for us over the last few seasons have very much warranted him being in that international squad."
Ruddy faces Southampton at Carrow Road this Saturday with Norwich on just one point, having drawn against Everton and lost to a 'soft' penalty against promoted Hull last week.
They did bounce back in midweek, however, defeating Bury 6-3 in the Capital One Cup, and Norwegian midfielder Alex Tettey is convinced Norwich are much improved from last season with Hughton having brought in six new players so far in the summer transfer window.
Tettey said: "We are looking good even though we drew at Everton and lost against Hull.
"Compared to last season we have a squad where two players are playing for every position. Everybody is pushing to play.
"You have to raise everything you do in training and in the matches. Every game is a big challenge. The Premier League is a very tough league."
Competition is particularly keen in midfield where Hughton has the likes of Tettey, Bradley Johnson, Jonny Howson, Leroy Fer and Anthony Pilkington to choose from.
And while Tettey admits he has not yet reached the form he demonstrated after signing for the club last season, it is not for the want of effort.
"I just have to keep working," he said. "As a player you are disappointed if you do not start a game, but if you get 10 or 15 minutes you have to come on and show the gaffer you should be in the team.
"They (the new signings) are really high-quality. You saw that on Tuesday. When they get used to everything they will play much better than they are doing now. They have already settled in really well but it takes time."