The bond between dogs and owners is similar to that of mother and baby, new research finds, but Australia's leading dog trainer says that is not an excuse to treat your dog like a human.

Researchers in Japan found that just by looking at each other, humans and dogs experienced a spike in the hormone oxytocin.

It is the same hormone that surges in mothers and babies when they exchange looks, and has a role in maternal bonding, trust and altruism.

The researchers watched 30 owners play with their dogs for half an hour, with a mix of breeds.

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"As the dogs gazed at their owner, the owner's oxytocin secretion got stronger," Azabu University's Miho Nagasawa said.

"And then that enhanced the owners to touch their dogs, and the nurturing and attachment behaviour got stronger.

"That led to the dogs' oxytocin levels [getting] higher, [and] made the dogs gaze at their owners more."

Their future research will examine if dogs can sympathise with human emotions.

Trainer Scott Donald has asked himself the same question after more than 30 years' experience in dog training in Australia and internationally.

But he warned people not to be too blinded by the puppy eyes.

He said he has seen increasing obedience problems as a result of owners treating their dogs too much like humans.

"I saw a photo of a [client's] dog on a lounge at home. He had no intentions of getting off the lounge and they were all going to work and he had his spot for the day," Mr Donald said.

"But he was a rottweiler. What happens is ultimately he may end up defending his little area."

He added that there was nothing wrong with treating a dog like a dog.

"They need to know where they fit and what you want for them. They'll do anything for you, they just need to know and it's up to you to train that," Mr Donald said.

"Otherwise their instinct just takes over — their natural canine instinct — and if we don't guide them sometimes the natural instinct is too strong and in some cases unacceptable."

During training, people should not rush to stare into the eyes of their four-legged friends, according to Mr Donald.

In some cases, too much eye contact can agitate dominant breeds, or overly excite the boisterous ones.

"I would teach people to practise no eye contact throughout certain training exercises because the eye contact has such a strong outcome for dogs," he said.