However, he admitted he might have come across as aggressive when he approached the worker.
"I told him to reverse his vehicle, go on the road and resume spraying up on the corner."
The resident was concerned the wind would take the substance, which he assumed was Roundup, a long way.
"I have a young family, children were about to come out from school. I don't want them rolling around and playing in stuff like that," he said.
Another resident also got involved when he attempted to break up the altercation.
Whanganui District Council, which contracts the weed-spraying, said if there was evidence of an alleged incident, it needed to be reported to general manager infrastructure Mark Hughes in writing.