Work on the new $8 million roundabout and underpasses at the intersection of Old Taupo Rd and Hemo Rd has begun after about six months of preparation work.
New Zealand Transport Agency Bay of Plenty state highways manager Niclas Johansson said the construction of a new roundabout at the State Highway 5/State Highway 30 Hemo Rd intersection is on track to be completed by July, about a year after construction started.
The 50m diameter traffic island is an effort to reduce crashes at one of the country's most dangerous intersections.
When complete it will also feature a 12m-high sculpture designed and built by an artist at New Zealand Maori Arts and Crafts Institute Te Puia, underpasses for cyclists and pedestrians, plus new entrances to Toi Ohomai Institute of Technology.
"The contractor has so far cleared the site, relocated services, installed a geothermal blanket to vent the steam, and begun the earthworks phase of the roundabout and the new alignment of SH5," Mr Johansson said.
"A temporary roundabout and bypass around Te Puia carpark is now in place so the formation of the new roundabout and underpasses can get under way."
The intersection south of Rotorua city was rated the fourth most dangerous in the country in a 2013 New Zealand Transport Agency report.
In the 10 years to the end of 2012 it was the site of 17 crashes, resulting in 23 people being injured. About 15,000 vehicles travel through there daily, 10 per cent of them heavy vehicles.