The council report, external, seen by the Local Democracy Reporting Service, said developers across the country were finding it difficult to secure housing associations to take on affordable homes, creating problems for schemes such as this one.
A similar situation arose last year at the Buckton Fields development in Northampton, where the council agreed to buy 36 new homes after a deal with a housing provider fell through.
The report said buying the homes would help increase the supply of affordable housing in West Northamptonshire and meet local demand.
The cost of the deal has not been made public, but the authority said it would be paid for using existing housing budgets and funding from Homes England.
The homes have not yet been built and are expected to be completed by late summer 2027.