Ten-digit dialing takes effect today in Nova Scotia and Prince Edward Island, but some callers are not hearing a reminder message when they skip the area code and use seven digits as usual.

The Telecommunications Alliance, which represents phone companies in Canada, said as of Saturday, all callers must include the area code when dialling. If they don't, they should hear a recorded reminder.

However, the system is being rolled out over a number of days.

A spokeswoman for the Telecommunications Alliance says each phone company is rolling out the messaging system to the network.

"So some people will hear the message today and some people may hear it only Wednesday this week," said Lucie Pugliese.