A company source said: "People are in the process of going now. They are being told, but they've been ready for this. Everything has changed since the construction sale and the new man coming in."
Bill Forrester became chairman two weeks ago. He replaced Sir Martin Laing.
A Laing spokesperson said the redundancies spanned the whole business, from support staff to executives. Some functions previously handled at Laing head office are now dealt with by the group's individual housing, property and investments businesses.
Laing has sold its headquarters building at Mill Hill and is leasing it back. The spokesperson said the firm intended to move closer to central London.
Laing is in the process of selling its property arm. It has received eight offers for this business, with Kier and Miller believed to be among those who have declared an interest.
Laing's last building subsidiary, Holloway White Allom, will be sold off separately.