A person can refuse a breath or saliva test if immediately after the requirement is made, the person produces to the police officer a certificate in the approved form from a doctor stating that:

• Due to an illness or disability, you cannot perform a saliva test.

• Providing the specimen would be dangerous to their health or cause medical complications.

• The certificate must be current, accurate, signed by a medical practitioner and addresses the persons medical reasons for non-compliance.

A person may also refuse a breath or saliva test if the police officer’s requirements was not lawfully made. This means the officer must have complied with the correct legal procedures when making the request for a saliva sample, failing to comply with the correct procedure can make the person’s refusal lawful.

For this defence to succeed, the person must satisfy the court that:

• The requisition to provide a specimen of breath or saliva was not lawfully made; or

• The person was, by reason of the events that occurred, incapable of providing the specimen as required; or

• There was some other reason of a substantial character for the failure to provide the specimen, other than a desire to avoid giving information that might be used in evidence.

Police officers must request breath or saliva specimens within three hours from when a person was driving, attempting to drive, or in charge of a motor vehicle. Any request made after this three-hour window can be deemed invalid.

This timing requirement is strictly enforced. Specimens collected outside this three-hour timeframe may be deemed inadmissible in court, and charges for refusing an invalid request typically can be dismissed.

For a specimen request to be valid:

• It must be made within three hours of the relevant driving activity, and

• The person must be driving, attempting to drive, or being in charge of a motor vehicle, tram, train, or boat, or

• Dangerously operating or interfering with a motor vehicle on a road or elsewhere.