The British Columbia MP is proposing to create a new tax bracket for individuals earning $300,000 or more.
And he's calling for a new corporate tax rate of 25 per cent for oil and gas companies.
For all other companies, Cullen would gradually reverse recent corporate tax cuts, raising the tax rate to 20 per cent from the current 15 per cent.
Cullen's call for the wealthy to pay more taxes is similar to one issued early in the NDP leadership campaign by former party president and longtime backroom strategist Brian Topp.
But Cullen contends his plan is "more moderate" than Topp's, striking a better balance between the need to raise revenue and promoting a healthy climate for business.
Indeed, the one-time small businessman is touting himself as more business-friendly than the typical New Democrat.
"I'm pro good business. I think that when business is done right it's a creative and hugely important process," he said in an interview.
"The fact that I have to say that tells me that New Democrats have at times strayed too far away from that sort of moderate, common-sense view of the economy. There's a role for government, there's a role for business and the private sector."
Topp has proposed creating a new 35 per cent tax bracket for individuals earning more than $250,000. And he's called for rolling back the corporate tax rate to 22 per cent.
Cullen's plan does not specify the tax rate he'd impose on those earning more than $300,000 but he said in an interview a rate in the low 30s would be "within the realm of reasonableness."
"I don't think it's all solutions to all things to say that we'll just simply tax the rich folks more and to tax so much that we'll drive them away. So you have to get the balance right," he said.
Cullen maintained it's also more balanced to ask oil and gas companies — "the most incredibly profitable industry on the planet" — to share a bigger tax burden than other corporations.
He'd plow one-third of the proceeds into incentives to support Canada's flagging manufacturing sector, another third into post-secondary education and the rest into general revenues.
Cullen said his plan is aimed at compensating other industries which have been "hammered" by the resource-driven high Canadian dollar. Moreover, he said it's an attempt to reap some broader, cross-country benefits from Canada's non-renewable energy industry before the resources run out.
He accused the Harper government of living "in a fantasy world where the golden goose will be forever."
"Right now, we're being irresponsible. It's a wild West attitude."
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