"It's one of the best Christmas presents we could ever get down home."
Mr Leach, who was stuck in traffic on the original 84-year-old bridge when a large bracket holding its swing structure came adrift in July, said the new crossing would "open the door a bit more" to Thames and the rest of the Coromandel.
He expected it to provide the biggest economic boost to the district since the road between Coromandel township and Whitianga was sealed in the 1990s.
Aucklanders would be able to drive to Thames without having to plan for the possibility of having to queue for up to an hour and a half while waiting for lights to change or stop-go controllers to let traffic through.
But Mayor Leach believed there would still be delays for traffic returning from the peninsula's east coast, until a roundabout could be built at the intersection of Kopu-Hikuai Rd with State Highway 26.
Although it has yet to confirm a date for opening the new bridge, the Transport Agency is organising a public walk over it on Saturday, December 10.
As well as having two traffic lanes, the new bridge has a shared walking and cycling path on its northern side and an underpass link at its eastern end to provide safe access to it from a proposed cycleway to be built between Thames and Paeroa.