Author: Bill Doogue
Practice area: Commonwealth offences
Bill is a founding Director of Doogue + George, ranked by Doyle's Guide as a Preeminent Criminal Defence Lawyer in Victoria (2026) and an LIV Accredited Criminal Law Specialist since 1998 with over 30 years of experience in complex criminal and corporate matters. His depth of experience in this area means clients receive accurate, considered advice.
View full profile →Bill authored this content and last revised it for accuracy on 7 August 2026.
What is the offence of Unauthorised Impairment Of Electronic Communication (Commonwealth)?
This Commonwealth cybercrime offence under section 477.3 of the Criminal Code Act 1995 (Cth) criminalises deliberate interference with electronic communications connected to a computer system without lawful entitlement. It targets conduct that disrupts or compromises the proper transmission of electronic data between computers.
Key points
- Legal elements: Causing impairment of electronic communication to or from a computer, knowing it was unauthorised.
- Type of conduct: Interfering with communications, including transmitting a computer virus to a private or government organisation.
- Court level: Heard in one of the higher courts.
The maximum penalty for Unauthorised Impairment Of Electronic Communication (Commonwealth) is 10 years’ imprisonment.
Common defences may include Factual dispute, authorisation, lack of intent, or duress.
Have you been accused of Unauthorised Impairment of Electronic Communication?
Police Interview
Prior to speaking to police, whether under arrest and in a formal interview, you should always request to speak to a lawyer. Our expert criminal lawyers are available and will provide you with clear and knowledgeable advice about whether to answer questions put to you by police, or whether it is in your best interests to exercise your right to silence and say ‘no comment’ so as not to harm a potential defence later on.
The police interview does not occur in a vacuum. Anything you tell police either during the interview or afterwards can be used against you if they decide it is helpful for their case.
Pleading Not Guilty
If you deny an allegation of Unauthorised Impairment of Electronic Communication, you should plead ‘not guilty’ and fight the charge. One of our expert criminal lawyers will analyse the police brief of evidence and identify those elements of the offence that police are unable to prove beyond reasonable doubt.
Our lawyers work closely with aptly qualified experts who can shed light on re-constructing what may have occurred.
Pleading Guilty
One of our specialist criminal lawyers will negotiate with prosecutors on your behalf to ensure that not only the charge is made out against you, but that the summary is agreed to. Your lawyer will tell your story to the Court to ensure that you receive the best possible outcome in your particular circumstances. It is important that a Judge know your personal circumstances and why you committed the offence. This insight generally leads to better outcomes.
Which court will the case be heard in?
This is a very serious offence that would be heard in one of the higher courts.
Examples of Unauthorised Impairment of Electronic Communication (Commonwealth)
- Sending a computer virus to a private organisation’s computer;
- Sending a computer virus to a government organisation’s computer;
What is the legal definition of Unauthorised Impairment of Electronic Communication (Commonwealth)?
Section 476.2 of the Act defines ‘unauthorised access’ as:
- access to data held in a computer; or
- modification of data held in a computer; or
- the impairment of electronic communication to or from a computer; or
- the impairment of the reliability, security or operation of any data held on a computer disk, credit card or other device used to store data by electronic means;
by a person is unauthorised if the person is not entitled to cause that access, modification or impairment.
Legislation
The legislation for this offence can be found on section 477.3 of Criminal Code Act 1995.
Elements of the offence
The onus is on the Prosecution to prove the following elements, beyond reasonable doubt:
- the accused caused any unauthorised impairment of electronic communication to or from a computer; and
- the accused knows that the impairment is unauthorised.
Can the Prosecution prove that you did not have authorisation?
Defences
If you have been charged with this offence, you may raise one of the following defences:
- Factual dispute;
- The fact that you were authorised;
- Lack of intent; or
- Duress.
You should call us to discuss your case with one of our experienced lawyers if you have been charged. Deciding on whether to plead guilty or not has huge implications for you and should be made after proper discussions with a criminal lawyer.
Questions in cases like this
- Did you interfere with the computer?
- Did you know that you sent a virus?
- Did you intend to interfere with the computer system?
- Did you have authorisation?
- Did another person force you to send the communication?
Maximum penalty for section 477.3 of the Commonwealth Criminal Code 1995
The court may impose a maximum penalty of 10 years imprisonment for Unauthorised Impairment Of Electronic Communication (Commonwealth) (s477.3 of the Commonwealth Criminal Code 1995).
Other important resources
