Lineups were reported at the Apple store in the downtown Toronto Eaton Centre and in Montreal at Apple's downtown location on Ste-Catherine Street.
The gold iPhone 5S was proving to be very popular, with reports of it selling out at some locations.
The Wall Street Journal says that Apple is asking suppliers to increase production of the gold-finish iPhone 5S in order to keep up with global demand.
Rogers spokeswoman Patricia Trott says due to a limited iPhone S5 inventory from Apple, demand is outpacing supply. Trott notes that consumers are particularly interested in the S5 model with the gold finish.
Telus spokeswoman Donna Ramirez said customers should come into stores to see what colours are available. If the colour they want is sold out, they can order it and have it shipped "as soon as possible."
It's the first time Apple is releasing two different iPhone models at once. The pricier one — the iPhone 5S, has a fingerprint sensor instead of typing in a four-digit passcode. Apple is selling the iPhone 5S from $719 and the iPhone 5C from $599.
The new iPhones went on sale at 8 a.m. local time around the world in countries such as the United States, the United Kingdom, Germany, France, China and Japan and also at some wireless carriers and retailers.