Youths caught in a crackdown on home invasions and carjackings will not be able to hide behind "sob stories" as an excuse for their violent crimes, says Victoria's premier.

Operation Cosmas has netted 129 arrests since May - mostly youths under 18 - over a wave of violent home invasions and carjackings across Victoria.

Premier Daniel Andrews said on Sunday some offenders were as young as 13, they come from a variety of backgrounds and were often repeat offenders.

Mr Andrews said while it was "sometimes fashionable" to talk about how people could have difficulties in life "no one will be accepting sob stories in the face of these violent crimes".

"Aggravated burglary, carjacking, home invasions, these sorts of crimes are completely unacceptable and no Victorian is prepared to excuse this sort of behaviour because you've had a hard deal in life or because your circumstances aren't how you'd like them to be," he said.

The Premier threatened that anyone caught "will be put inside" and "feel the full force of the law".

"This is unacceptable in a modern Victoria, we will not make excuses for it, we will not seek to explain it away, we will instead make sure Victoria Police has the powers and resources they need," he said.

Deputy Commissioner Andrew Crisp said it was a "significantly worrying trend" that it was a smaller number of offenders, committing more crimes, at a younger age.

Mr Crisp moved to reassure the community police were working to keep them safe and feeling safe, including extra night patrols to increase visibility.