Victorian criminals have been listening in to police radios to find homes with gun safes to burgle.
Criminals listening to Victoria Police conversations on analog radios are tracking firearms safety officers and breaking into homes they visit to steal guns.
Acting chief commissioner Tim Cartwright said an upgrade of the radio system - now on its way - was much needed.
"This was the greatest threat to the operational safety of our members, particularly in rural Victoria," he told a public accounts and estimates committee on Tuesday.
Firearms safety officers had to stop telling the operations room where they got out of their cars to check on secured guns.
"(Because) soon after that visit, we (would) have the property burgled," he said.
Police Minister Wade Noonan said the government had provided $11.5 million to upgrade the rural radio system, with Victoria Police finding a further $23.8 million.
Mr Noonan also said police officers were now patrolling in pairs to reduce the threat of a terror attack.
Interim safety arrangements, which have been in place for six weeks, mean single-officer patrols are no longer allowed.
Mr Noonan said custody officers would be recruited to guard prisoners at police stations, freeing up police to get back on the beat.
"The 400 custody officers are very clearly about returning police to the front line," Mr Noonan said.
A hearing into the Corrections Department revealed nine breaches by registered serious sex offenders since the start of 2015.
Six breaches were for non-compliance, while three were for sexual offences.
Earlier, Education Minister James Merlino said Victoria will chase the federal government for about $1 billion not yet set aside for the final two years of the Gonski education funding agreement.
Mr Merlino said the state was committed to finding funding for the final two years of the funding agreement in 2018 and 2019.
"We are going to pursue the federal government for years five and six," he said.