Overflow from the Hinemoa Street pumping station started at 9.18pm, 12 June and stopped at 11.02 pm 12 June.
Council's environmental health officers will be inspecting the areas for any visible signs of contamination. Warning signs have been erected advising against swimming in, or fishing from the stream.
Water quality testing is currently being undertaken.
For further information contact David Tu - Environmental Health Officer on 04 5706 779