Traffic management measures and speed restrictions would be in place.
Hamilton City Council city development manager Andrew Parsons said work would start on the southern side of the bridge.
"The clip-on will accommodate a shared cycle and pedestrian path, and will enable the bridge to cater for two lanes of traffic in each direction. This is an important component of the overall project so it is exciting to see this work get under way," he said.
The ring road project will cost more than $100 million and has taken four years of planning.
Art will be incorporated into the project, including blue and yellow panels fixed to pedestrian handrails on the bridge clip-on, to represent the sky and kowhai flowers.
The recently completed Highland Drive retaining wall before the approach to Pukete Bridge features the Maori proverb: "Nga Tapuwae o Hotumauea The sacred footprints of Hotumauea of Ngati Koura who leapt across the Waikato River".