The 32-year-old is one of several players currently on loan at Portman Road, but he has insisted that it is the loan players that are showing they care more about Ipswich's fate than the club's contracted players.
Wellens told the Daily Express: "A new manager needs to come in and put a rocket under their backsides because there are not enough people who show they care about losing a game of football or even their own careers.
"One of the coaches said that the old manager got stick for bringing in loan players, but it is the loan players who are showing they care and that is a sad indication of what is wrong.
"We need people to show passion, to show they care. It is difficult when you are getting the ball and no-one else wants it. It is human nature when you are under pressure to go and hide but we need a better attitude, and to act like men."
Ipswich are currently five points from safety at the foot of the Championship table.