Khan, 29, has been out of action since mid-2015 when defeating American Chris Algieri after waiting in vain for a clash with former stablemate Manny Pacquiao to come to fruition.
The WBC recently named Khan mandatory challenger to the vacant world title fight between Danny Garcia and Robert Guerrero, although Warren revealed a couple of fights he would be willing to sign off on in the meantime.
“(Amir Khan) should consider my offer to him of a fight with Bradley Skeete at welterweight, or if he finds any excess pounds he may have accumulated through his inactivity hard to shed, with our WBO super-welterweight champion Liam Smith,” said Warren.
“Both are attractive matches that would fill any arena in Britain, where he needs to re-establish a home following.
“I have always liked like Amir and I admire the work he has done for many charities and the less privileged, as well as in areas of distress around the world. Yet once again he has missed out on a boxing biggie as well as being by-passed in the Honours List despite being such a fabulous ambassador for sport.
“Khan has wasted almost two years abortively chasing fights against the Money Man and Pacman and has nothing to show for it. Surely he cannot be happy to use up another five months of his career waiting on the (Kell) Brook fight.
“The danger is that hanging around for so long could well diminish any hunger he has left for the game,” he added.