OTTAWA - The CRTC says phone numbers on its do-not-call registry now will be off-limits to telemarketers for five years instead of three.

The federal regulator says the extension will automatically apply to the more than 6.7 million telephone numbers already on the list, as well as new registrations.

The agency has also clarified two other rules.

One change will exempt political candidates not affiliated with registered parties from the do-not-call rules.

The other change covers organizations that use auto-dial and computer calls for non-telemarketing purposes -- debt collection for example.

It says they must follow CRTC rules limiting the times of day they can make such calls only if there are no provincial laws governing hours of use.

The do-not-call list is a free service which allows people to reduce the number of unwanted telemarketing calls and faxes they receive.

Numbers can be registered at any time by visiting www.dncl.gc.ca or by telephone at 1-866-580-3625.