Road workers were verbally abused, and objects thrown at them by people travelling through the Te Puke Highway site this morning, the NZ Transport Agency says.
Work to stabilise the Kaituna riverbank began on Monday, meaning the Te Puke Highway will be reduced to one lane and with Stop/Go traffic management for up to three weeks.
The agency said in a statement the road works were causing delays as anticipated.
Police had been contacted over "unacceptable driver behaviour" at the roadworks and there are plans to install security cameras.
"It has come to our attention our crew is getting verbally abused and objects thrown at them from disgruntled people", said Rob Campbell, Waka Kotahi NZ Transport Agency regional manager for maintenance and operations.
"Our contractor is working hard to complete this work in the shortest time possible, and while we realise delays can be frustrating, this behaviour will not be accepted."
He said the agency understood Te Puke Highway was already experiencing travel delays late afternoon and early evening, but this work must be done now or there is a risk the road will slip away.
"We're asking people who travel through the site to be respectful of the Stop/Go crew and be patient. This team is working hard to keep traffic flowing while the bank stabilising is underway. They also have the right to feel safe and to go home to their loved ones afterwards."
The Stop/Go team is actively monitoring traffic to minimise delays when possible, especially between 4pm and 7pm.
Drivers were encouraged to use the Tauranga Eastern Link toll road if they could to reduce pressure on Te Puke Highway.
The agency has removed the toll on the westbound lanes heading towards Tauranga while this work is underway.
The toll-free period runs until June 3, for westbound traffic only, between 4pm and 7pm, Monday to Friday.