Canada's seniors have edged out the number of children under the age of 15, according to the latest population figures that experts say contain further evidence of a long-projected shift in the country's demographic makeup.

The latest round of data released by Statistics Canada on Tuesday show seniors made up 16.1 per cent of Canada's population as of July 1, 2015, compared to 16.0 per cent for children between the ages of 0 and 14.

The figures show a fundamental shift in Canada's composition and signal that the time to confront looming challenges is at hand, said Amanda Grenier, director of McMaster University's Gilbrea Centre for Studies in Aging.

Grenier said Canadian policy-makers need to emulate policy-makers around the world by reconsidering "how to organize society" to cater to the needs of an aging population.

"We haven't necessarily had the national debates we should be having around aging," Grenier said in a telephone interview. "That could be on dementia, that could be on care, that could be on cities. We have a bit of catching up to do as a country."

StatCan said the latest figures were driven by a trend that took root in 2011 and has continued to accelerate -- the aging of the baby boomers, or Canadians born between 1946 and 1965.

The agency said the population growth rate for Canadians over the age of 65 was 3.5 per cent, nearly quadrupling the national average of 0.9 per cent.

Baby boomers now account for 30 per cent of the senior demographic, the agency said.

Demographer David Foot said the latest figures still represent the early days of a trend that is likely to persist for at least a decade. StatCan seems to agree, projecting that Canadians over the age of 65 will make up a fifth of the national population by 2024.

Foot said the most serious implication of this shift, namely an increased toll on Canada's health care system, won't be felt for some time.

"They're still fairly young seniors. They're in their late 60s," Foot said of the boomers. "Many of them are still working and paying taxes."

Grenier said urban planners would also be wise to begin adapting their techniques and marshalling their resources to accommodate the needs of a population that tends to be less mobile than their younger counterparts.

Western University social demography professor Don Kerr said the economic implications of an aging population are also being powerfully illustrated in countries across Europe and Asia, many of which he said have a significantly higher proportion of senior citizens than Canada currently does.

He cited Japan as an example of a nation that has had to grapple with a dwindling labour force and higher national debt levels influenced at least in part by its shifting demographic makeup.

"Any effort to plan ahead and ensure that we have time to accommodate it, that's wise public policy," Kerr said of Canada's fledgling shift.

The aging of the Canadian population has also begun to make itself felt in provincial figures in recent years, with Nova Scotia, New Brunswick and Newfoundland and Labrador all reporting that deaths have begun to outpace births.

This aligns with StatCan's latest data, which found that Atlantic Canada had a higher proportion of Canadians over the age of 65. Seniors comprised 19 per cent of New Brunswick's population, making it the most aged province in the country. The most youthful region was Nunavut where just 3.7 per cent of the population are currently senior citizens.

While Canada's year-over-year population growth was the highest among G7 countries, StatCan said the 0.9-per-cent increase was the smallest of its kind since 1998-99.

The slower pace was caused primarily by a drop in international migration growth, which slipped from 0.7 per cent in 2013-14 to 0.5 per cent this year.

The agency said 86 per cent of Canada's 35,851,800 residents were located in Ontario, Quebec, Alberta and British Columbia.