The blue heeler cross chihuahua was less than two years old, and the family had raised her from the age of eight weeks.

After scouring the neighbourhood, putting up posters and notifying all the lost pet services, the family grew suspicious.

Three weeks on, there has not been a single sighting of their beloved miniature blue heeler and they're considering the possibility that Patch was stolen.

And she isn't the first placid-looking pup to disappear in suspicious circumstances in Canberra recently.

While about 20 pets get reported missing daily to the Facebook site Canberra Lost Pet Database, half of those are found within a few hours.

Cats are more likely to stay missing for longer than dogs, according to the Facebook site's founder Anna Reimondos.

Patch's owner Katie Gabriel said one of the hardest things about the dog's disappearance was trying to explain it to her young children, aged two and four.

"We are very upset," Ms Gabriel said. "The four-year-old doesn't understand where she's gone, and I have a two-year-old who keeps going looking for her. They keep asking when she's coming home.

"We've had no information, no sightings, and we expected to have her home by now."

The family's ordeal started on Tuesday, August 3.

The dog, who sleeps inside, became restless about 4am and Ms Gabriel took her to the enclosed backyard to do her business. She then settled in her kennel. Three hours later when Ms Gabriel went to take her breakfast, she was gone.

"Patch is a small to medium size dog and she just looks like a blue heeler but small," Ms Gabriel said. "The only thing chihuahua about her is her size."

It's those unique features that Ms Gabriel believed would make Patch desirable to another family.

While they have no proof, they haven't been able to find anywhere she could have escaped from.

"We believe she may have been taken from the yard," Ms Gabriel said. "She's friendly and she's not aggressive, so she would have gone up to somebody."

The story is similar for a number of small dogs across the region.

Ms Reimondos said, while 99 per cent of people do the right thing, there had been cases when owners had questioned where their dogs had ended up.

Kingston resident Ben Carter said his dog Fluffy, a poodle cross jack russell, went missing about a month ago. He also scoured the neighbourhood, letterbox dropped, put up flyers and contacted the right agencies.

Two weeks ago, he received three tip-offs from people who had seen his flyers, telling him they'd seen a similar dog being called by the same name at a nearby home.

Mr Carter visited the address multiple times but no one answered the door. He hesitated before calling the police to report it.

Mr Carter said police visited the home and the occupants answered the door, but officers were unable to see the dog.

"The police said to me to keep a lookout because they said it's not an uncommon occurrence that the dog is released once the people know the police are involved," Mr Carter said.

He said she had escaped the yard before, but she'd always come back soon after.

"If someone sees a dog that looks large or mildly aggressive, they will probably call someone because that dog could be a threat to people.

"With our little dog, there is no way in the world she's a threat, she's the total opposite," Mr Carter said.

Canberra Pooch Rescue founder Maree Sheahan said she believed circumstances like these were becoming more common.

"These dogs are never to be seen again, and it's not like they're being killed on the road because Domestic Animal Services would see them," she said.

"You can't hang on to people's dogs just because you think you'd like that dog."

A spokesman for Transport Canberra and City Services said it encourage the public to report lost dogs. In 2015-16, 1437 dogs were impounded into Domestic Animal Services.

"If someone finds a lost dog, the first step is to check if the animal is wearing an identification tag with a contact number," the spokesman said. "They can also take the dog to a vet clinic where its owner may be identified if the animal is microchipped.

"It is important for people to remember if they find a lost dog, until proven otherwise, it belongs to someone. If the dog cannot be reunited directly with the owner ... the animal must be handed in to DAS."