The Australian Cyber Security Centre (ACSC) under Mr MacGibbon was made part of the Australian Signals Directorate (ASD) by former prime minister Malcolm Turnbull in January 2018.

While Mr MacGibbon won't be leaving until May 28, his resignation does come in the middle of a federal election campaign.

Elections in other nations have been prone to cyber attacks in recent history.

Announcing the resignation on Saturday, ASD director-general Mike Burgess praised Mr MacGibbon for his fierce advocacy for the importance of cyber security for the community, businesses and governments.

"He is indeed the face of cyber security in Australia and, through his leadership, helped raise the nation's cyber security standards," Mr Burgess said.

"His work in response to the recent compromise of the Australian Parliament's computer network is a good example of how Alastair and his team have made an important, practical difference to cyber security in Australia."

ASD principal deputy director-general Lieutenant General John Frewen will add the leadership of the ACSC to his responsibilities until Mr MacGibbon's replacement can be found.

Australian Associated Press