LONDON, ON - Canada wants to open its doors to more foreign-trained doctors and other professionals to meet demand, getting qualified immigrants out of taxi cabs and corner stores, Immigration Minister Jason Kenney announced Tuesday.

Using London Health Sciences Centre as a backdrop, Kenney announced a sweeping overhaul of the immigration system aimed at clearing a backlog of cases.

Another objective is to push those who can work in Canada in areas such as engineering, skilled trades and medicine to the front of the list.

"We believe newcomers are key to our future prosperity," Kenney said. "It's critical our immigration system respond to current and future shortages and across the spectrum of the labour market."

Though the changes will affect all professions, health care is at the top of the list.

"Too many newcomers find themselves unemployed or underemployed, including medical professionals stuck in survival jobs," Kenney said.

But the Ontario College of Physicians and Surgeons questions the need for the immigration changes.

In 2011, Ontario licensed more foreign-trained doctors than Canadian - 1,500 to 1,300 - and has made strides in addressing doctor shortages, meaning qualified international doctors are working here and the unemployed do not meet standards.

"If they're qualified, if they meet criteria, they'll get a licence. The number of licences we have issued to international graduates has tripled since 1997," college spokesperson Jill Hefley said.

But there are "acute" shortages in smaller rural areas that will grow as the health sector is hit with a wave of retirements, Kenney said, and immigrants can help address the labour shortage.