Balfour Beatty Engineering Services is set to cut 35 M&E and plumbing jobs in London and the South-east as it pulls out of the region.
A number of workers in Leeds and Newcastle are also facing redundancy, the contractor said.
The firm said it was making cuts in London and the South-east after deciding to no longer pursue work as a tier two subcontractor in the region.
It also cited a “number of historic contracts” coming to an end as a reason for the cuts.
In a statement today, Balfour said: “This week we commenced redundancy consultations with 35 mechanical and plumbing skilled operatives working in our Engineering Services business in London and the South-east.”
“This is as a result of our decision not to pursue work in the London and South-east area as a tier two subcontractor, as well as a number of our historic contracts in this difficult market coming to an end.
“We are also in consultation with a small number of monthly paid staff and operatives in our mechanical and plumbing workforce in Leeds and Newcastle due to a number of projects having completed.
“We are looking to redeploy impacted individuals wherever possible.”
The contractor is currently undergoing a consolidation process, after it posted a series of profit warnings during 2015.