Photo: The Canadian Press

The federal government has been warned to take a cautious approach to publicly debating immigration over fears of reaching a "tipping point" that could undermine public support for welcoming immigrants.

Internal data prepared by the Immigration Department for a committee of deputy ministers shows a majority of Canadians support current immigration levels, but this support drops when they are informed of how many immigrants actually come in every year.

Government was advised to tread carefully in any high-profile debate on immigration levels when engaging with the public on the issue.

Keith Banting, research chair on public policy at Queen's University, has studied Canada's changing perception of multiculturalism policies and says he has seen a growth in overall support for current immigration levels.

But when it comes to increasing the number of immigrants, opinion becomes more divided.

Banting says he believes government is nervous about public willingness to accept a dramatic shift in immigration levels.