In Sydney's inner west alone, 4500 people have demanded action be taken against problem pooches in the past three years – a rate of 30 complaints each week.

And while the City of Sydney is currently fielding 90 general canine-related complaints every month, that figure is likely to spiral in coming months following the introduction of new strata laws that make it easier for tenants to keep dogs in apartment complexes. Under the relaxed guidelines, introduced several weeks ago, owners corporations can no longer automatically refuse pets in units.

Mark McCrindle, whose company's research into pet ownership and unit dwellings helped shape those reforms. said: "Dogs have always been part of the suburban landscape. They're a fixture of Australian life. However, what has changed is we have become more densified in terms of population. Blocks are smaller. Unit living has become mainstream and people want to replicate suburban living in those situations. They want the barbecue on the balcony, they want to invite people over and they want to be able to have pets."

Almost 40 per cent of households across Australia now count a dog as one of the family. But most of those houses have people who go to work daily, leaving animals alone, with some people either oblivious to the repeated barking that neighbours are forced to endure, or, immune to the torture it has triggered.

Nowhere is the "dog divide" deeper than in Sydney's inner west. Prior to becoming part of the Inner West Council, Leichhardt Council's call centre was dealing with 1000-dog related disputes annually, with a further 450 fielded by nearby Marrickville. It would appear that, in addition to those complaints, some residents are attempting to resolve matters themselves. A fortnight ago, Fairfax Media highlighted a growing trend involving anonymous, angry notes that are left in Sydney streets by neighbours, for neighbours. Many of those relate to dogs.

While ceaseless, unflagging yapping appears to top the list of pet hates, it is the "irresponsible" pooch owners themselves who run a close second.

In a recent passive aggressive note, one Erskineville resident raised the issue of "constant barking" by offering "solutions" that included the purchase of an RSPCA-opposed "citronella collar" which sprays a dog's face with scent every time it barks.

The neighbour continued: "I do not wish to call the council ranger but cannot continue to live with this" before signing off: "I wish you the best and hope Molly settles soon."

In the same suburb, someone felt compelled to nail a board to a tree and remind dog walkers that public spaces are "not a dog toilet", adding: "Please pick up the poo after your dog daily ... we are sick of doing it for you."

Another anonymous resident, meanwhile, scrawled this third – and apparently final – warning on the back of an envelope before taping it to their neighbour's mailbox:

"Your dog is a big problem," it stated bluntly, adding: "Do something about it or I will be forced to take action."

Bark Busters is a dog training business which began in Wollongong 27 years ago and now has offices worldwide. Australian director Val Edwards said: "I have seen many threatening notes that people have slipped under the door anonymously. They can be extremely distressing for the owners, many of whom have no idea their dogs even bark in their absence."

Mr McCrindle said growing friction over dog etiquette is another indication of how attitudes have changed, adding that today "we have higher expectations of our domain and the community conforming to our standards".

"If you took your dog for a walk 20 years ago, nobody thought to bring a plastic bag to pick up droppings. But now, it's a social faux pas if you don't – if not a violation of local government acts.

"That shows just how much society has changed – yet dogs haven't been on this course. Dogs are dogs ... they bark, they sometimes whine and yap. They haven't been gentrified along with people. That's part of the challenge."

They say that moving house is one of the most traumatic events in anyone's life.

But nobody warned five-year-old Bailey the cocker spaniel that the adage applies to dogs too.

After uprooting to Sydney's lower north shore, Margot Davis and her daughter Emily sensed that her beloved Bailey was suddenly "pining" whenever she walked out of the door. She had no idea how much – until he was suddenly branded neighbourhood nuisance number one by nearby residents.

Several days after moving into his new home, an unattended Bailey dug a tunnel under the fence and escaped.

A week or so after his return, Ms Davis found a "passive aggressive" note on her windscreen from a neighbour, advising that Bailey was "howling" non-stop and "frightening" her neighbour's children.

When a horrified Ms Davis texted the number provided to both apologise and say thank you for bringing the issue to her attention, she inadvertently opened a channel for all-out war. "I got some very rude phone messages and texts," she said. "I responded by saying that 'I do care, I'm sorry I've disturbed your children but I'm also quite distressed that I have a dog that is suddenly very unhappy'.

"What came back made me fearful that they would actually do something to hurt my dog."

After Ms Davis turned to dog training specialists Bark Busters, Bailey's separation anxiety was swiftly ironed out and today he is back to his best. "I've owned many dogs over my life but he is the warmest, most loving I have ever known," said Ms Davis.

Bailey's trainer Sharon Birrell said the dispute was "typical" of many that escalate across Sydney's suburbs each week. "These cases often start with an anonymous note," she said.

"Many of those are really nice, well-intentioned letters to simply let the owner know there is an issue. But sometimes, the language is overtly threatening, sometimes it's implied threatening. And then there are the notes that refer to poison being thrown over the fence."