A Wairarapa iwi will be raising its concerns with the Greater Wellington Regional Council over a popular patch of watercress that was sprayed by the council's contractors.
A creek that runs alongside Manaia Road southeast of Masterton where the watercress grows was sprayed with herbicides.
Watercress is used in a 'boil-up' and is considered to be a traditional Māori dish and an important part of mahinga kai (traditional food gathering).
General manager of Kahungunu ki Wairarapa P.J. Devonshire said his organisation would be asking the council why it did not consult tāngata whenua.
"We've discussed it already and we all need to talk some more ... and we like to think we have a good relationship with Greater Wellington Regional Council. with our chairperson being the chair of their iwi group, Ara Tahi.
"So, we will be talking to them and finding out what was it all about, was there a real need to do it, was there something else that has happened?
"Here we are talking about the waterways and the mauri (life force) of waterways and mahinga kai and all of those kinds of things and this waterway is definitely a mahinga kai for our people, and it definitely has a good mauri going through there."
Mr Devonshire admitted that he was also personally upset with the watercress patch being sprayed because it was one of the most accessible places to gather the kai.
In the meantime, he said, Kahungunu ki Wairarapa would be using social media such as Facebook to spread the message that it was unsafe to pick watercress from the site.