Health groups joined forces with the Conservative opposition to accuse the Liberal government of trying to raise tax revenue on the backs of vulnerable diabetics.

Farmers, doctors and other small business owners who legally engage tax levers are hardly cheats plundering the national treasury.

Canada's finance miniter was in Oakville, Ont., for a town hall meeting where a question-and-answer session boiled over more than once into a shouting match.

"Parliament, and not the government, is the final authority on taxation," said Conservative finance critic Pierre Poilievre.

The plan has prompted complaints about wealthy small business owners being given an unfair tax advantage.