Two police officers who were shot dead while on duty in a rural Australian town have been named, as a massive search continues for their alleged killer.

Victoria Police identified the victims as 59-year-old Detective Neal Thompson - a local officer on the brink of retirement - and 35-year-old Senior Constable Vadim De Waart.

The pair had travelled to the property in Porepunkah, north-east of Melbourne, alongside eight colleagues to execute a warrant for alleged sexual offences. Another officer was seriously injured in the shootout but is recovering after surgery.

Police say the suspect - named as local man Dezi Freeman, 56 - is heavily armed and still at large more than 24 hours on.

Thompson joined the force in 1987 and worked with the major fraud and crime squads before moving to the town of Wangaratta - an hour from Porepunkah - in 2007. A great lover of the outdoors, he was planning for his imminent retirement.

In a statement, Victoria Police Chief Commissioner Mike Bush described the loss of these officers as a devastating loss which struck at the heart of both the policing family and the local community of Porepunkah.

Officers, helicopters, and armoured vehicles are searching the thick bush where Freeman has vanished, with local authorities warning residents to stay indoors until he is apprehended.

The situation remains tense and unpredictable, with authorities emphasizing the need for vigilance and caution in the area.