The Hereford based firm specialises in manufacturing steel power pylons.
It has been part of Balfour Beatty since 1995 and operates within the power networks divisions.
Painter Brothers currently employs 60 people.
A Balfour spokesperson said: “We have commenced formal consultation with employees who work for our Painter Brothers business in Hereford about our proposal to reduce the workforce due to a reduction of demand in the overhead line market and an increase in competition.
“We remain committed to a sustainable Painter Brothers business and the first class service we offer our customers.
“Our proposal will align the size of our workforce to our current and forecasted order intake.
“There are 60 employees within our Painter Brothers business. As we are in formal consultation it would be inappropriate to comment further.”