Workers were given the news this week by Chief Executive Officer John Murphy.
Emails seen by the Enquirer state: “We appreciate that the decision to reduce holidays to 21 days is a difficult one but believe it is the right one for us to ask the business to accept and is less impactful than a broader range of salary reductions which have been implemented by a number of our industry peers.”
Reduced holiday entitlement will run for the year from February 1 2020 to January 31 2021.
Staff will also get the usual Bank Holidays off but will have to save four days of annual leave for Christmas.
The 10% salary sacrifice is not expected to last beyond the end of July.
One staffer said: “Most of us will lose between six and nine days holiday on top of the pay cut.”
A Murphy spokesperson said: “We are making a temporary change to our people’s terms to ensure that when we come through this challenging lockdown period, we have the people and skills ready to continue delivering our essential projects safely and to continue investing in the economies where we work.”