The Australian Signals Directorate (ASD) is the whole government response by the Australian Federal Government. The page, in the very first sentences state:
ASD is committed to making Australia the most secure place to connect online. We do this by comprehensively understanding the cyber threats, and providing proactive advice and assistance to improve cyber posture and resilience risk management by government, businesses and the community.
The page is full of useful resources, many of a policy and governance nature, but also includes links and phone numbers to report incidents and issues to.
Go to https://www.asd.gov.au/about/what-we-do/cyber-security for the ASD Cyber home page!