Meanwhile, house prices have accelerated at an unimaginable pace, pricing out everyone from the most vulnerable to those with professional jobs, as record numbers of homeless people move on to the city's streets.

Sound familiar? The city is not Sydney, but Vancouver.

It has been grappling a housing affordability crisis for over a decade, leaving it mired in the same problems that now grip Sydney, and dominate conversations from the backyard barbecue to the country's highest paid policy wonks.

Vancouver mayor Gregor Robertson, now in his ninth year in office - a tenure that has been dominated by the worsening crisis - can spot the parallels with Sydney from a mile away.

"It took cities like New York and London a generation of global capital influx to skew their real estate prices. Vancouver has happened in a decade, at most," he said.

"My sense is Sydney is in a similar predicament."

Part of the problem, he said, is that Australia and Canada were "way behind in innovation in government" and cities were left with few real policy levels to tackle the issue.

"Cities need to have more self-determination and powers to take care of people.

"The symptom of the housing affordability crisis exposes the much bigger structural problem in government that we need to fix."

In recent years, Sydney has narrowly bumped Vancouver from second spot in an international ranking of the world's least affordable housing market, outstripped only by Hong Kong.

Mr Robertson's experience trying to alleviate the crisis with the limited tools of local office, and against political intransigence in higher levels of government, will form the basis of his keynote speech at Sydney's Town Hall on Tuesday night.

Last year, Mr Robertson was forced to re-write his signature 10-year housing plan after it failed to deliver on its key goal - to end homelessness in Vancouver by 2015.

"We didn't get there by 2015. In fact, the situation has worsened. It's moved right up into middle income. Now we're deploying new tools."

The policy "reset" now includes strategies to directly link new housing supply to income levels, a 1 per cent tax on empty homes, regulation of short-term rental accommodation such as Airbnb, and releasing more city land to be redeveloped for affordable housing.

Mr Robertson attributed the failure of the earlier plan, in part, to a lack of support from provincial and federal governments. "When those two levels of government don't take care of business, the impact is in the city."

Sydney and Vancouver's situations aren't a mirror and different jurisdictional limitations constrain the type of policies councils can pursue.

But the difficult politics of housing affordability has shaped Sydney's dilemma, particularly when it comes to altering generous taxation arrangements around property, such as negative gearing.

Last year, former NSW planning minister Rob Stokes was quickly slapped down by his federal colleagues after he called on the Turnbull government to reform the negative gearing rules.

And in NSW council elections, held on Saturday, local campaigns against perceived overdevelopment featured prominently across Sydney, and was claimed by Labor and the Greens as a core reason for the swing against the Liberal party.

This disconnect between a need for more housing and a grassroots reluctance for more development is "delicate balance", Mr Robertson said.

"In cities like Vancouver and Sydney, where the growth pressure and global capital are daunting forces, it does pit communities against developers and elected councils."

But Mr Robertson said the tide was turning, in Vancouver at least, where housing forums and council meetings once dominated by the "nimby crowd" were now seeing a "surge of advocacy" from the next generation of young professionals and families "who want to live in the city and cannot access housing".

"Urban issues and affordable housing are now vote-determinant issues. People really care and they are demanding change."

Mayor Gregor Robertson is a keynote speaker at the City of Sydney's CityTalks event on Tuesday night at Town Hall. Tickets are FREE from Ticketmaster.com.au.