TORONTO - Premier Dalton McGuinty is warning of multi-year deficits for Ontario, starting with a "significant" shortfall this year.

While he wouldn't confirm estimates that the deficit would come in at about $5 billion, McGuinty told The Canadian Press that conclusions could be drawn based on the numbers that are already out there.

The governing Liberals forecast a $500-million deficit in their fall economic update, but have since recently hinted that the figure may turn out to be much larger.

McGuinty has committed to matching federal dollars for infrastructure projects in the province and providing $1.3 billion to bail out troubled automakers.

McGuinty also acknowledged that his five-point economic plan may not be enough and that he'll have to "drill deeper" to get the province back on track.

The premier says the economy won't come back as strong unless fundamental changes are made, such as increasing business investment and having more workers with post-secondary education.