TORONTO -- Major shifts in the economy have pushed more of Ontario's workforce into minimum-wage jobs -- more than double the share from nearly a decade ago, a new study shows.

Nine per cent of Ontario workers earned the minimum wage in 2011, up from 4.3 per cent in 2003, a Toronto policy research organization said in a report released Tuesday.

"When we think back to what happened in the economy between 2003 and 2011, there's been a lot of big changes," said the report's author, Sheila Block.

"We had a real hollowing out of jobs in the middle of the labour market... the loss of those middle-income jobs, a lot of it attributable to the loss of manufacturing jobs, is one factor," she said.

"The other factor is I think we're still feeling the after-effects of the 2008 recession in the labour market," she said.

The study by the Wellesley Institute is based on Statistics Canada data.

Certain population groups -- such as women, recent immigrants and visible minority workers -- were more likely to be working for minimum wage eight years later, according to the study.

More than 10 per cent of women worked for minimum wage in 2011, compared with 7.6 per cent of men, it said.

And while young people made up the bulk of minimum wage workers in 2011, the data show nearly 40 per cent were 25 or older.

"We used to think of the minimum wage as kind of teenagers who were working to buy the latest phone app and really that's not the case anymore," Block said.

"We're seeing both more adults staying in those minimum-wage jobs and we're also seeing that those jobs aren't distributed equally across the economy," she said.

Increasing the minimum wage would help reduce income inequality, she added.

"Since greater shares of recent immigrants and racialized Ontarians work for minimum wage, an increase in the minimum wage would contribute to closing those gaps," the report read.

It would also contribute to closing the wage gap between men and women, it said.

The Ontario government has faced pressure from advocacy groups to raise the minimum wage to $14 an hour from the current $10.25, which is on par with British Columbia.

In the remaining provinces and territories it ranges from $9.95 to $11.