"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."
Green, who has only played once for England, added: "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 undervalued.
"The situation here leaves a question mark whether the club are rewarding success and you end up questioning yourself and questioning your future.
"I was a professional at Norwich for 10 years and associated with the club for nearly 15. So I think I have proved I am loyal. I am not looking to jump ship for an extra fiver."
But West Ham chief executive Scott Duxbury hit back at Green's comments and claimed the goalkeeper was wrong to say he was not valued.
Duxbury said: "Less than a year ago, Robert Green entered into a five-year contract. The club were delighted to recognise his status as our No1 goalkeeper and rewarded him with this long-term deal.
"At that time, he requested a mechanism to review the terms in the summer of 2009. This was and remains the appropriate time to review."
Green has yet to speak to manager Alan Curbishley about his future but Duxbury insisted the keeper will not be leaving Upton Park.
He added: "We value Robert highly, that is why we gave him a five-year contract less than 12 months ago. We have no intention of selling him and do not propose to comment on this further."
