The Mohaka Bridge stretch of State Highway 5 between Napier and Taupo will be operating under a 30km/h speed limit as a standard repair and maintenance programme is carried out over the next three days.
Contractors will be working beneath the bridge and the work is being carried out in the wake of annual maintenance inspections which took place earlier in the year.
Both lanes will remain open during the work.
"Our team is working under the bridge to upgrade some of the bolts and the lower speed limit will help ensure that the bridge does not vibrate too much so the work can be completed safely and efficiently," NZ Transport Agency regional transport systems manager Oliver Postings said.
Contractors got to work on Monday and the work is expected to be wrapped up on Thursday, and during that time the 30km/h limit will be in place.
It is the fourth bridge on SH5 to come in for work this year.
Munns Bridge and Waipunga 2 and 3 bridges have undergone maintenance.
The Napier-Taupo highway has also seen work carried out just north of Hill Culvert where rumble strips have been installed along with structural line-marking between the intersection with SH2 at Eskdale and Te Pohue.
Mr Postings said spring and summer was a busy time for road repairs and motorists can expect to see general maintenance being carried out on several sites along SH5.
They could also expect to see speed restrictions in place.