The dye was also observed along parts of Hewletts Rd.
The council said people who drove through Newton St last night or this morning should rinse their tyres on grass if possible, rather than concrete, to avoid the dye going into the stormwater system.
If any of the dye gets into the stormwater system, there may be some blue discolouration.
Newton St remains open with traffic management in place until the dye is cleaned up, which the council expected to be the end of today.
Fulton Hogan and Downers were managing the clean-up on behalf of the company involved and working with both councils.
A Tauranga resident, who asked to remain anonymous, said he saw the spill as he drove along Newton St for work.
”The splatter area was about a metre wide at its narrowest point.
“It looked like a truck had been leaking fluid. Based on where I was driving to and from it seemed to run the whole length of the road.”
The resident said the liquid looked purple where it was dry and blue where the substance was still wet.
”I could see where the truck turned into a … yard and then pulled back out on to the road. It went under the Hewletts Rd underpass but then my route took me away from it.”
The resident said he could see contractors pressure-washing the road.
”It’s important for people to know about this especially if it’s invading the water.”