The contractor’s temporary accommodation firm has been hived off to Wernick Hire for £11.7m.
While Ashtead Plant Hire has bought the mechanical plant and small tools unit for £4m.
As part of the sale, Kier has entered into trading agreements with each buyer to secure continued supply for its jobs.
Kier has retained certain parts of its other plant operations , together with its fleet management business, for use by the group.
Paul Sheffield, chief executive of Kier Group, said: “It is important for Kier to respond to changing market conditions and, by focusing on our core business and building on our strengths, we can ensure that Kier remains a strong and resilient business and continues to grow in our chosen markets.”