The federal government is about to introduce stricter rules about foreign takeovers of Canadian companies.

Ottawa says it's time that Canada creates a built-in mechanism to turn down takeovers that could compromise our national security.

Â鶹´«Ã½ has learned that an announcement expected Tuesday on the subject will try to address critics' concerns about foreign ownership without scaring away international investors.

The Conservative government wants to tightly limit the definition of national security, so that the regulations do not become a protectionist catch-all.

"We don't want national security to become an excuse for protectionism as it can and has in some other countries," said Prime Minister Stephen Harper last week.

Takeovers in Canada's oil patch and resource sector by state-owned companies from countries like China first raised red flags. There have also been several other high-profile cases of foreigners buying up Canadian companies in the last two years.

Steelmaker Dofasco, Hudson's Bay Company, INCO, and ALCAN are just a few national icons no longer under Canadian control.

"Even the Montreal Canadiens, for goodness sake," New Democrat Peggy Nash told Â鶹´«Ã½. "So, certainly there's a question of national pride involved. There's a question of strategic importance for some of these industries."

When Industry Minister Jim Prentice outlines the new foreign takeover rules in Vancouver Tuesday, he'll have to try to satisfy the concerns of politicians like Nash and the public about the loss of Canadian sovereignty.

But the new rules may not go far enough to satisfy critics. Conservatives say he will also have to carefully explain the new rules without spooking markets and frightening investors.

With a report by CTV's David Akin in Ottawa