The environmental impact of the spilling of up to 3000 litres of diluted weed spray into a Waikato stream is yet to be seen, according to the regional council.
The incident occurred when a small weed-spraying truck veered off Waihi's Waitawheta Rd after the driver was blinded by sunstrike about 7.30am.
The driver suffered minor injuries, Waihi police Acting Sergeant Wayne Harper said.
A statement from the Waikato Regional Council said it appeared the spill had little environmental effect but people were urged to remain cautious over contact with the stream.
The Taiari Stream flows into the Ohinemuri River.