Immigration Minister Jason Kenney acknowledged he was prompted to introduce changes to Bill C-31 by months of outrage from refugee advocacy groups and opposition critics.
"I believe it's not right for the government to take the position that the original bill is the only option possible," he said.
"I'm open to other reasonable ideas ... and I believe the modifications are in agreement with our objectives."
The Protecting Canada's Immigration System Act makes several reforms to the refugee system, and the Conservatives say it's designed to crack down on bogus refugee claims.
Among other things, the bill would see people who are designated as part of a "mass arrival" detained for a year before the decision to imprison them was reviewed.
That measure is designed to address the recent arrivals of boatloads of migrants and deter future ships.
Kenney said Wednesday that provision will be changed so that a review will take place at the 14-day mark and then again 180 days later.
"The intention has never been to maintain refugees in detention," he said.
"The intention is to have a greater ability to process smuggled migrants who arrive in large numbers."
The year-long detention had been a significant issue for advocacy groups as the Supreme Court had ruled in 2008 that unreviewed detentions violate a person's rights.
The fix introduced by Kenney may not solve the problem, said Rob Shropshire, interim executive director of the Canadian Council for Refugees.
"Certainly knowing that at least there will be a review before 14 days, that's a good thing," he said.
"But then if they are still going to go back and only make it every six months, that remains a serious concern."
The legislation will also be changed to make clear the government won't revoke permanent residency status for refugees when the situation in their home countries improves.
The bill, as it was written, could have seen refugees who visited their now-peaceful countries of origin lose their permanent residency status in Canada.
Earlier Wednesday, the New Democrats said they wouldn't support the bill without reforms.
NDP immigration critic Jinny Sims said the changes will be studied at committee.
"What we have heard overwhelmingly from witnesses in the past two weeks is that this bill is fundamentally flawed," she said in an email.
"It will do nothing to prevent human smuggling, while punishing refugees."
Kenney wants to see the new bill passed by June in order to override a refugee reform bill passed by Parliament in 2010 which would come into effect by then.
That bill, passed during the Tories' minority government, had several clauses changed as a result of negotiations with the opposition and received all-party support.
But the new bill revokes some of those compromises.
Kenney said the government simply isn't operationally prepared to implement the earlier version of the bill.
Shropshire said there are still other concerns with the new bill.
They include a section that allows the minister to designate some countries as "safe" and means that people from such countries won't be able to seek refugee status.
It's still not known which countries will be on that list, though Kenney insisted Wednesday it won't be arbitrary.
But Shropshire said there are still problems with that list, pointing to the situation of Roma refugees from Hungary or the Czech Republic.
If those countries are placed on the list, they won't be able to claim refugee status despite the fact they face widespread persecution.
Shropshire said he isn't optimistic the government is open to further reforms but hopes the bill could receive further study in the Senate.
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