we call it "probation" in Canada. Its usually 3-6 months
Though I think they can withhold benefits for longer than that separately from the probation period, but that's kind of rare I think.
Really withholding benefits in Canada is pretty different than in the us, though, since here it means you don't buy glasses for three months and there it means you'd better not break your legs.
(IANAL)
edit: I am in Ontario and I know a guy in the medical feild that had a 1 year probabtion