Engineering and environmental consultancy White Young Green has expanded further in Ireland.
WYG Ireland, which has offices in Belfast and Londonderry, has snapped up PH McCarthy & Partners in a €19.5m deal.
PHMP is one of the Republic's leading engineering consultancies with offices in Dublin and Limerick.
It specialises in large public infrastructure projects in the water and highway sectors and has a large private client portfolio in the buildings sector, according to WYGI.
The deal means WYGI has expanded its workforce across the island to 670; PHMP has a 184-strong team and all its directors are joining the WYGI senior management team.
Ray Moore, group managing director of WYGI, said: "We are delighted to welcome such an experienced team as PH McCarthy to our business.
"This is our largest acquisition in Ireland to date and is an important step in the development of WYG Ireland.
"I have no doubt PHMP's expertise and experience will significantly enhance White Young Green's reputation and business position in Ireland."
Donal O'Connor, MD of PH McCarthy, said: "We are delighted to be joining this growing and exciting business."
WYGI's services include civil, structural, mechanical and electrical engineering, environmental services, town planning, quantity surveying and project management.