Water quality advocates have criticised Horizons Regional Council's reporting of water quality at summer swim spots.
They say negative results have been glossed over.
Choose Clean Water believed the council had misrepresented the "traffic light" measurement of water quality for swimming.
A Horizons' environment committee report refers to amber as being "satisfactory for swimming".
"Actually that's not what LAWA (Land, Air, Water Aotearoa) say; that's not what the Ministry of Health says," Choose Clean Water spokeswoman Marnie Prickett told the Chronicle.
The LAWA website defines amber as "alert" and "caution" and a Horizons sign at Mowhanau refers to amber as "could be a health risk".
"Our issue is with the amber value," Miss Prickett said. "They are misrepresenting what it means and that's our big concern."
She said that using the word "satisfactory" gave a completely different sense in public health terms.
"It's alarming because the public rely on Horizons to give accurate information."
She said the council didn't need to spin water quality data - "Let's celebrate what we've got and work through making the sites that are polluted, better."
Horizons said "alert" and "caution" was the Ministry of Health terminology for amber, while "satisfactory" was the language council used. It was updating signage around the region to match.
Horizons senior scientist Maree Patterson said a river at an amber stage meant the E. coli (for freshwater) or enterococci (for the coast) levels had reached a certain concentration.
"These levels haven't changed in classification, however we understand that different terminology can be confusing," Mrs Patterson said.
Meanwhile, Horizons council candidate Nicola Patrick took issue with a Horizons press release which said summer swim spots in the region were safe for most of th summer. Ms Patrick said it appeared not to include swim spots such as the Whanganui River at the Town Bridge and Mowhanau Stream.
"It appears these two sites are not counted as coastal swimming sites in the report so their results have been glossed over," she said.
Both sites reported unacceptable results on seven out of 24 and 25 samples respectively; and were graded as amber on six and seven occasions.
"Less than half the times these sites were sampled were they identified as safe for swimming," Ms Patrick said.
Horizons spokesman Logan Brown said the sites were considered in the environment committee report and council was aware of the higher levels of E. coli in the Mowhanau stream and its popularity as a swimming spot.
"In the past five years, Horizons - in conjunction with landowners - has completed nearly 15 kilometres of fencing to exclude cattle and have planted 34,000 native trees and shrubs along the Mowhanau Stream to help improve water quality," he said.
"This has seen positive changes in the Mowhanau Stream, as highlighted in the report. We will continue to work in the Mowhanau and Whanganui catchments in the aim of improving water quality at both sites, and we intend to investigate the source of the E. coli contamination in the Whanganui River at the Town Bridge."