Canadians won't see changes to Old Age Security until at least 2020, Finance Minister Jim Flaherty said Friday.

That means Canadians 57 and older should be able to expect to get the same benefits as seniors collecting them now.

The government has said any changes wouldn't affect anyone now collecting OAS, but hadn't given a specific date for when it expected the program to see cuts.

"This is not for tomorrow morning," Flaherty said in Oshawa, Ont., at an event with Conservative MP Colin Carrie.

"This is for 2020, 2025, so that people who are middle-aged and younger today, like Colin and not me, can be assured that they will have the social programs, properly funded, fiscally responsible. They will be here for them in the future."

Flaherty said the plan will be outlined over more than one budget.

That timeline would put the government well past the next federal election, which is in 2015, and possibly the election after that.

Liberal finance critic Scott Brison said the government is manufacturing a crisis to attack Canada's most vulnerable citizens, low-income seniors.

"It’s nuts. It makes no sense from a public policy perspective. If there were a crisis, there are other ways that you would act that would not be as regressive," Brison said.

Brison said 40 per cent of Canadians getting OAS make less than $20,000 a year and more than half make less than $25,000 per year.

Changes could also affect the poorest seniors who get the Guaranteed Income Supplement, because they have to qualify for OAS to get the GIS, he said. 

NDP deputy seniors critic Lysane Blanchette-Lamothe said the government still hasn't said what measures it will take to change the program.

"It's been weeks that we've been asking the same questions," she said.

"Are you going to touch the age at which people can access Old Age Security, yes or no? It's a very simple question."