The 28-year-old was hoping to have talks over a new contract after a successful campaign last season, which saw him voted Player of the Year.
"No matter what the figures are in the workplace in terms of wages, you either feel a valued member of your staff or you don't," Green told The Sun. "At the moment, I don't and clearly West Ham don't care about me.
"We've a whole host of players who have arrived on a lot of money since the takeover and, fair play, you take what you can get and I have no problem with that.
"Some of them have played, others have been injured, but I feel I have played a part and been good value.
"If you put the strongest West Ham XI out, I'd be the lowest earner by a long, long way. I do not even want to be close to the top earner at the club - I don't care about that. I would just like some parity.
"Other guys are getting rewarded but I'm not. It's been reported that one player has been offered so many millions to go away.
"He could be rewarded with a £3m pay-off while I would like to tie myself down to the club and they have turned around and said 'no thanks'.
"I am not getting in the England squad at the moment and I'm not getting European football, but I love it here, which is why I want to sign a long contract. The fans here are fantastic. Why would I want to leave?
"After asking for a long-term contract, the club turned around and said 'no' without a real explanation.
"It wouldn't have been as bad if they had said no and then given their reasons.
"The club might say 'you don't need to sign a new contract as you've got three years left'. Fine. But how highly do they value me as a player? Realistically, look at Dean (Ashton) who has signed a new contract this summer. Good luck to him. Brilliant.
"He's a great player and I have no doubts he will become an England regular.
"Obviously, West Ham value him a hell of a lot more than they value me. In fact, I feel completely under-valued."