He is asking dog owners to ensure their dogs are contained, saying they could face court action otherwise.
"Often people think if their dog is at their back door when they go to sleep and is there in the morning when they wake up, it's been there all night," he said.
"However, often it's been up the road, grabbed a few of its mates and has been worrying stock during the night.
"The only way to ensure your dog is home and where it should be is to chain it up or put it in an enclosure like a kennel and run. Be a responsible dog owner."
Lewer said when the council informed owners their dog had been worrying or attacking stock, they were often surprised and shocked, believing it was not capable of such behaviour.
However, Lewer said while dogs had been domesticated, those instincts were still there. Wandering dogs and stock have also caused serious injuries and deaths on the district's roads.
In his 35 years on the job, he has seen six or seven deaths and countless crashes related to wandering stock, the most recent occurring last month.
Edgecumbe woman Elizabeth Edwards was killed when her car collided with a horse on Te Teko Rd late at night in May.
Lewer said Te Teko Rd was one of the worst in the district for wandering stock along with the areas around Waimana, Ruatoki, Minginui and Ruatahuna.
The council has installed signs in these areas to warn visitors of the danger.
Lewer asks that owners of stock, particularly horses, which cause the most issues, to ensure fences are in good condition and that gates are closed. If you live in an area where people come onto your property and leave gates open, he recommends you install a padlock.
Owners of wandering stock and dogs can face court action as well as having their animals euthanised.
If a dog is on private property and actively worrying stock or acting threateningly, the property owner is within their rights to shoot and kill the dog.
The dog's owner can also be held liable for any costs or loses incurred.
Many car crashes are caused by people swerving to miss dogs, however, if a dog is hit by a car its owner is liable to repair the car.
Lewer said if people saw stock on the road, they should call animal control immediately.
The council runs a 24-hour service which could be reached on 3060500. Once phoned, they aim to have the problem solved within an hour.
The council can also provide humane dog traps, which have a high success rate trapping dogs that habitually wander onto private property at night.
