The industry figure claimed she has lost belief in the lenders and their attempts to reach suitable agreements regarding the resolving of disagreements over foreclosure practices.
Such disputes arose after attorney generals from all 50 states announced a probe into bank foreclosures in 2010 when it was claimed faulty documents had been used in order to seize property.
The five largest mortgage servicers in the US - JPMorgan Chase, Citigroup, Wells Fargo, Ally Financial and Bank of America, which has a history of more than 200 years - have since been negotiating a settlement with the officials.
Ms Coakley stated: "I have lost confidence that the banks will bring to the table an agreement that properly holds them accountable for wrongful foreclosures."
She added her office has therefore begun preparing for litigation.
By Asim Shah