Millennials have overtaken baby boomers as the dominant generation in Canada for the first time, thanks to an immigration surge, the national statistical agency said Wednesday.

The demographic change, noted last July but only now reported by Statistics Canada, also saw the proportion of the population aged 15 to 64 years increase -- easing concerns of a looming major labour shortage as large numbers of boomers retire.

"This change may benefit Canadian society by increasing the size of the working-age population, possibly helping to alleviate the pressures of sectoral labour shortages," Statistics Canada said in a report.

"However," it added, "the high number of new working-age Canadians may also put pressure on the delivery of services to the population, housing, transportation and infrastructure."

The agency noted that the proportion of the population aged 15 to 64 years had been declining steadily after peaking in 2007.

That changed with the arrival of more than one million immigrants in the 12 months to July 1, 2023, "many of whom were younger than the average or median age of the population," it said.

The baby boomer generation, born between 1946 and 1965, became the largest cohort in Canada in 1958, seven years before the last baby boomer was even born, and held this status for 65 years.

Millennials were born between 1981 and 1996.

According to Statistics Canada population projections, Generation Z could overtake millennials in numbers between 2038 and 2053.