"It's a bit different from the old one-way bridge. Very nice and very exciting to be first," Cooper said.
At a dawn blessing, Te Uri O Hau kaumatua Hone Martin gave the new bridge its name Te Ao Marama Hou which translates to "moving from the past into the future".
NZTA's senior manager project delivery, Chris Hunt, said the new alignment and bridge are unsealed and may be closed again to protect the road surface if there is bad weather associated with Cyclone Oma this weekend.
"At this stage the bridge and alignment are only open to one-way traffic, heading east," Hunt said.
"We urge motorists to drive with caution over the new alignment, don't be distracted by the new environment and keep to the temporary speed limit."
West-bound traffic will continue to follow the signposted detour just before Anderson Bridge and travel along Matakohe East Rd before rejoining SH12.
"West-bound traffic will pass Matakohe School and drivers are reminded to take extra care, watch out for children and keep to the 50km/h speed limit."
In about two weeks, from March 4, the new highway alignment will be extended another 600m towards the second new bridge that will replace Hardies Bridge.
The two new two-lane bridges and 2.5km of road realignment will remove tight curves and short straights to improve safety on this section of the Twin Coast Discovery Route.
The $26 million project is expected to be completed mid-2019. For more on the Matakohe Bridges Project, see www.nzta.govt.nz/projects/connecting-northland/matakohe-bridges/