"The seals like to lie on the sand in the sunshine or they come up on to the sand dunes to rest. And people will walk right past them with their dogs that they can't control, and they disturb the seals."
She is not anti-dog - she has two dogs of her own - but if she spots seals on the beach, she puts her dogs on their leashes.
Ms Brummer said she has observed a lot more seals at Longbeach this spring than in previous years.
She is angry by what she calls a "lack of respect" for the beach and its inhabitants. She often finds rubbish that people have left on the beach.
"If we want visitors to enjoy our beaches, we have to stop dumping rubbish and allowing the seals to be killed," Ms Brummer said.
"If you can't control your dogs on the beach, please put them on a leash."
Jasmine Hessell, conservation partnerships manager with the Department of Conservation, said dogs and motorbikes were the two biggest threats to seals that come ashore on beaches.
"We really can't emphasise enough that people need to keep clear and need to keep their dogs away. You should keep at least 20m away and not get between the seal and its escape route to the sea."
Ms Hessell said spring was the time of year when seal pups were weaned and learning to make their own way in the world.
"So it's common for seal pups to come ashore to rest, particularly after a storm."
She said it was an offence under the Wildlife and Marine Protection Acts to deliberately kill or injure seals.
If you find a seal that has been injured or is in an unsafe area, or you see people or dogs worrying seals, phone DoC on 0800 362 468.
