The president of the autonomous Papua New Guinea province of Bougainville estimates that the time it takes to travel between Buka and Arawa has been practically cut in half with 15 new bridges now in place.
Up till now the trip has involved the fording of the rivers.
The Japanese Government had funded the construction of the bridges and the ambassador, Hiroharu Iwasaki, was in the province to open them last week.
President John Momis says the completion of the bridges is a reflection of the landowners and government working together successfully.
"That is something the people really appreciated. It is a success story of collaboration with the landowners, because, as you know in Bougainville the land where the bridges is owned by the landowners, not by the government, so it is a difficult thing to negotiate. So in this instance the landowners agreed to have the land contributed for the public purpose."
John Momis says all that is required now is for the road to be sealed and some causeways to be mended.