His comments came as Human Resources Minister Diane Finley admitted Thursday that the government hadn't conducted studies on the potential impact of the reforms.
As protesters were kept away from the Premier Tech plant where Harper was announcing a $9.2 million loan, the prime minister pointed a finger at unions for creating some of the turmoil around changes to the program.
"It's important to say that there's a lot of misformation on this," Harper said.
"I read that some unions were saying we're cutting seasonal workers. That is completely false. We have no intention of doing that."
Harper said that EI will be available to seasonal workers who can't find work in their region.
Besides the protests near the plant, where new investment is estimated to help add 200 jobs to the company workforce of 2,300, there were also demonstrations in Ottawa.
Representatives of the Confederation of National Trade Unions and the Quebec Federation of Labour delivered 10,000 postcards and a 25,000-name petition from Quebec workers denouncing the reforms.
The issue has been pressed as well in recent days by Quebec Employment Minister Agnes Maltais, who questioned her federal counterpart Wednesday about the possible effect of the reforms.
Quebec is particularly interested in EI reforms because the province is seeking to wrest control over the program away from the federal government in a bid to expand its powers.
Finley acknowledged Thursday that detailed studies on the effects of the EI reforms had not actually been conducted.
Maltais "wants details that don't exist," Finley said, while adding that several analyses had been conducted as the bill for the reform was drafted.
"We're going to monitor the progress of the program and if there is a need for changes, we will make adjustments."
Maltais said during a news conference on Wednesday that such an approach "made no sense." Opposition parties also criticized the government, calling its actions irresponsible.
"We cannot go into people's lives with a complete improvisation like this, without knowing the consequences for the regions, for families, workers, and industries," said NDP critic Alexandre Boulerice.
Finley announced major EI reforms last May that are now being phased in.
The changes include an expectation that claimants accept any job for which they're qualified, within 100 kilometres of their home, as long as the pay is 70 per cent of their previous salary. They must also prove they're actively seeking work.
Detractors of the plan say it unfairly targets Atlantic Canada and Quebec, where there are a number of seasonal industries such as forestry and fishing.
In Riviere-du-Loup, Harper defended the program, saying it was changed "to encourage more flexibility."
He said the government's priority is to create jobs in every region of the country.
"When families need protection and are vulnerable and have paid into the system, the system will be there for them and that's a commitment that we've made and will adhere to," he said.
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