The Daily Mail says Nigel de Jong, Vincent Kompany and Micah Richards are unhappy with the new deals offered to them, especially after learning that City are paying club record signing Aguero £200,000 per week in a five-year deal confirmed.
Holland midfielder De Jong revealed how he had already grown 'frustrated' at the way contract negotiations had progressed and it has since emerged that talks have broken down.
Kompany and Richards also feel undervalued by their big-spending club.
Richards has been offered a five-year deal worth £65,000 a week while Kompany has been told to expect a four-year deal worth £80,000 a week. However, the pair are mulling over the offers.
Full back Richards has publicly stated his desire to stay at the club and rejected claims he was looking for £100,000 a week.
Kompany, who was in last season's PFA team of the year and is City's player of the year, is a candidate to skipper the side if Carlos Tevez leaves.
But Kompany and Richards will hold out for deals they feel represent their standing as important first-team regulars.
A City source said: "While efforts to bring the club's wage bill into line are commendable, it doesn't wash with the key members of the squad being offered less than half of what some of the top earners like Yaya Toure, Carlos Tevez and Sergio Aguero will earn.
"All the players are keen to stay and play their part in City's success, but they don't want to feel forgotten about."