Silent lines | The Telecommunications Industry Ombudsman
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Silent lines

Australian landline numbers and the addresses to which they are connected are, by default, listed in public number directories and given out by directory assistance services.

A telecommunications provider can agree with a consumer to:

  • not list their landline number and address in public number directories
  • keep their landline number from being displayed to the receiver when the consumer makes calls, unless they manually override this feature.

This service is commonly known as a silent line service. The provider can charge a fee for this service.

The feature of a silent line service that keeps unlisted numbers from being displayed is called calling number display blocking.

Complaints we commonly receive include claims that:

  • a silent line has been agreed to but not provided
  • an unlisted number has been published in a printed or online public number directory or disclosed by a directory assistance service
  • calling number display blocking has not been activated for a silent line.

We generally do not consider complaints that are solely about a provider’s commercial decision to charge for a silent line, unless the provider had previously agreed not to charge.

There are also some circumstances where a phone number will always be disclosed, even if it is unlisted, for example when a call is made to emergency services (000).

Laws and codes of practice

The following laws and codes of practice are relevant to silent lines.

Our approach

When we deal with silent line complaints we consider the law, good industry practice, and fairness in all the circumstances.

The law

An individual’s phone number and address are generally considered personal information under the APPs. See our guidance on Personal information (Australian Privacy Principles) for more information about personal information and the APPs.

The Telecommunications Act generally prohibits disclosure of an unlisted number and associated address. This includes publishing this information in a public number directory.

The Customer Service Guarantee Standard sets timeframes for activating and fixing calling number display blocking.

Good industry practice

In circumstances where a provider is not required to comply with the APPs, the Telecommunications Consumer Protections Code obliges the provider to protect a customer’s personal information from unauthorised use or disclosure.

The Calling Number Display Guideline sets out the following obligations for unlisted landline numbers:

  • a provider must automatically block calling number display for unlisted landline numbers unless the consumer agrees otherwise 
  • calling number display blocking must operate across all networks, and
  • calling number display must be active for all calls to emergency services.

Telecommunications Industry Ombudsman view

When a consumer applies for or makes changes to a service, and asks for a silent line the provider must clearly state if it can provide a silent line, and how much it costs.

During a transfer, if a gaining provider is aware that a consumer has a silent line and there is a problem with keeping the silent line active after the transfer, the provider must tell the consumer immediately and give them the option to cancel the transfer. See our guidance on Transfer of services - in detail for more information about provider obligations during a transfer.

If an unauthorised disclosure of an unlisted number or associated personal information has occurred the provider must rectify the disclosure as soon as possible.

When the disclosure puts the consumer’s safety at risk we encourage the consumer to take immediate steps to protect themselves (for example by finding alternative temporary accommodation).

Dealing with a dispute

We may deal with a complaint about a silent line as an urgent complaint if we think following standard timeframes may expose the consumer to a risk to their health or safety. Our procedures for handling urgent complaints are set out in the TIO Complaint Handling Procedures.

When dealing with these complaints we may ask for:

  • call recordings or other evidence to establish if the consumer asked for a silent line
  • bills to establish if the provider is charging for a silent line
  • a copy of any valid waiver of the consumer’s rights under the Customer Service Guarantee
  • evidence of any disclosure of an unlisted number, for example directory listings
  • evidence of the effect of an unauthorised disclosure of an unlisted number.


If our view is that the provider did not follow the relevant rules or APPs, we expect the provider to address the impact of the contravention on the individual.

When an unlisted number has been disclosed without authorisation outcomes may include:

  • giving the consumer a new unlisted number
  • removing any published information from print or web media
  • refunding charges for the silent line for the period the number was disclosed
  • compensating the consumer:
    • for financial loss incurred as a result of the disclosure
    • for injury to feelings and humiliation caused by an interference with the individual's privacy
    • under the Customer Service Guarantee Standard for delays in activating or fixing calling number display blocking.

Effective date: 11 March 2016

This page provides broad guidance on the law, good industry practice, and what the TIO may consider to be fair and reasonable in general circumstances. It is not a full statement of the law or good industry practice. The TIO considers each matter brought to it on its own particular merits.