Australian group Downer EDI is buying New Zealand builder Hawkins.

Downer describes the acquisition as a strategic move to complement existing capabilities and provide a platform for growth into the Pacific region.

Hawkins is one of New Zealand’s biggest builders, with current major contracts including Wellington Airport's new control tower, Christchurch's town hall and Auckland's Park Hyatt hotel.

Downer chief executive Grant Fenn said the acquisition would allow his company better access to New Zealand’s booming non-residential construction industry, where an estimated $NZ50 billion ($A45.9 billion) is forecast to be invested over the next five years.

Hawkins will reportedly retain its current branding.

The buyout is expected to be complete by March 31, funded through existing debt facilities.

Mr Fenn added that the firm will be earnings accretive in its first year.

Downer has been shifting to the rail, transport services and technology sectors in the hope of offsetting continuing declines in its core mining services business.

Downer’s repositioning allows it pick up increasing investment and outsourcing in the public transport, communications and defence sectors.