The NDP leader told a CBC radio program last weekend that the oilsands are artificially inflating the Canadian dollar and hollowing out the country's manufacturing sector.
He called it the definition of Dutch disease — a reference to the Netherlands and how a natural gas find in that country led to declines in manufacturing in the 1960s.
Mulcair also told the radio program he wants to see the oilsands developed in a responsible way that sees more refining done in Canada and less raw product sent abroad.
Redford said Thursday she's not sure whether Mulcair's comments were informed or just his opinion.
But she added she hopes he explains his motivation because she says someone looking to lead the country one day needs to understand just how important the oilsands are to the entire country.
Earlier this week, Saskatchewan Premier Brad Wall also took issue with Mulcair's comments.
Wall said if Mulcair thinks the oilsands are a disease, Wall wants to know what the NDP thinks the cure is.
Redford also spoke Thursday night at Progressive Conservative party fundraising dinner in Calgary.
All 1,750 tickets to the $500-a-plate event were sold.
At a news conference before the dinner, Redford was asked how she intends to woo back Calgarians who voted for the Wildrose in the recent provincial election.
"We've put what was a pretty negative-toned campaign behind us," she said.
"We're going to be able, as a government and as Progressive Conservatives, to talk about how we want to change government, how we've already begun to change government, how we're thinking differently in terms of how we're delivering services, what our fiscal plan is.
"We're going to continue to be fiscally responsible and socially progressive. We are going to ensure the programs being provided by government are achieving the outcomes that Albertans expect."
(CHQT, The Canadian Press)