Around 30 job cuts are being targeted from a total staff of around 180. Although it is understood up to 70 jobs are technically deemed to be at risk as part of the restructuring.
The whole John Sisk & Sons construction business employs around 500 staff and delivered revenue of around £344m in the last publicised accounts.
The southern region shake-up comes six months after former Kier chief operating officer Steve Bowcott replaced Garry Crabtree as managing director of John Sisk & Son.
A spokesman for the firm said: “The Sisk UK South regional construction business is determined to remain competitive and meet the challenging market conditions this year with a strategically focused but reduced workload.
“It has therefore become necessary to consolidate this business and unfortunately, the company envisage they may have to make approximately 30 redundancies in order to achieve this consolidation.”
The changes are understood to include a new management structure going forward.