Chief executive Andrew Davies has also warned that employees could soon be asked to taker similar salary cuts as the situation develops.
He said managing directors and heads of business function would continue to identify ways to reduce costs within the businesses.
Managers are also being told to keep under review and, where appropriate, terminate the appointment or engagement of temporary workers or contractors as soon as it is practical to do so.
Exceptions may be made for business-critical appointments or engagements.
Davies set out the measures in a circular to all staff seen by the Enquirer.
He also underlined that sites and depots would remain open until it became necessary to change the policy.
The leadership team’s base salary cuts will come into force from 1 April and end of 30 June.
The group has yet to decide whether this year’s annual pay review will take place, while any other pay reviews have been halted.
Kier has implemented a recruitment freeze and is offering staff unpaid leave.
In the circular, he said: “We will continue to review the level of work available to all employees as client and customer needs develop.
“If there is a material decline in work available, then it will be necessary to implement further measures, which will include asking certain employees to take unpaid leave.
“We will be seeking guidance as to whether the Government’s scheme to pay a proportion of workers’ salaries would apply in such circumstances and, if so, how.”
Davies warned: “As you can see from the Prime Minister’s updates, this situation is changing by the day, and time is of the essence.
“We felt it was important to announce these measures now, so that you have the latest information with which to make the right decisions for you and your families.”