Pellets discovered at the Wakapuaka Sandflats on Monday sparked an urgent response fearing a high toxicity to dogs have turned out to be non-toxic.
DOC director terrestrial biodiversity Hilary Aikman issued an apology on Tuesday following the scare.
Nelson City Council sent contractors to the popular dog walking site in northern Nelson on Monday afternoon to remove what was thought to be highly toxic blue or green pellets.
Hilary says the pellets were laid as part of a trial testing the effectiveness of a drone.
"DOC scientists used a drone as part of a trial on a small area of mudflats at Wakapuaka sandflats. They used non-toxic pellets for this research, dyed blue to make them easier to see.
"Once the pellets were laid out, a drone was used to photograph the area where the pellets lay, to quantify pellet detection rates.
"We would like to apologise to Nelson City Council and members of the public, particularly dog owners for the concern this caused.
She says the non-toxic pellets should have been removed on the day of the trial and not doing so was "an error in judgement".
