Taieri MP Ingrid Leary said it started off as a beautiful sunny day and she was looking forward to getting to her electorate.
She smelt the faeces before she saw it, strewn across the hood of her car.
The incident was unlikely to be opportunistic because of the significant amount of faeces, which were hard, suggesting they had been collected over several days.
While she said she was not an expert, she believed it was dog excrement.
She laughed because the situation was "so incredibly funny", but also sighed because she felt sorry for the person who had dumped the excrement.
"I just think they could have saved both themselves and me a lot of effort if they’d just contacted me to have a bit of a yarn rather than go to such extraordinary lengths to vent their frustration."
She could not draw any conclusions about either the identity or the motivations of the mystery poop dumper.
The poop was cleaned off using detergent, hot water and an old scrubbing brush which was then thrown out before she took a shower.
Her attitude to the incident was a little bit flippant, as she had constituents who were facing "massive issues" around inequality and were struggling day to day with life, which put the defiling of her car into perspective.
However, there was a deeper issue about the attitudes of people to politicians.
She could have just cleaned the car and moved on, but she felt it was important to have discussions about what is and is not acceptable behaviour towards public figures.
People did need to have "an incredibly thick skin" to be in the role, as it drew a lot of criticism.
Having posted about the incident, people were drawing conclusions about who it might have been despite there being no evidence.
"If the person does hold anti-government sentiments, they might have shot themselves in the foot by doing this," Ms Leary said.
