What killed a dog that had been walking in a popular Whanganui dog-walking park remains a mystery after tests proved inconclusive.
One dog died and at least two others fell ill last week when visiting the Otamatea Reserve.
The Whanganui District Council warned dog owners to keep their pets on a leash when visiting the park and there had been concerns the illnesses were related to rat bait.
Tests were carried out on the dead dog at Whanganui Veterinary Services after the owner informed the council of the death last Friday .
"Further tests have been performed since the death of a dog last week following a visit to the local dog park," said veterinarian Gemma Pouls.
"Although initial concerns were for rat bait toxicity, these tests have been inconclusive, and do not support rat or slug bait toxicity.
"Unfortunately the exact cause of death is unknown. We have been working closely with the family affected, and our thoughts are with them during this difficult time."
The result will leave a cloud over Otamatea Reserve, which is where the Wanganui Dog Obedience Club is based and is due to celebrate its 60th anniversary in a couple of weeks.
The club also has a major competition at Otamatea at the end of this month .
The club's president, Kathy Kerr, said it would go ahead with the event as long as nothing else of concern happened between now and the time of the competition on the weekend of October 27.
Kerr said there was a strong desire among dog owners to know what had happened and to reduce the spreading of rumours.