Victorian police will be given new powers to lock up one-punch killers if Labor wins this year's election, but the government says the laws will allow offenders to escape full responsibility.
A new offence of assault causing death will be created, which the state opposition says will help police in cases where they are unable to secure a murder or manslaughter conviction.
Shadow Attorney-General Martin Pakula said there had been cases in the past where a person had been able to argue their way out of a manslaughter conviction and been acquitted altogether.
"(The police) will still charge with murder or manslaughter, if they are confident they can get a conviction for either of those offences, but in circumstances where they are in doubt, rather than have the risk of someone being acquitted altogether, they will have the option of charging the offender with the assault causing death," Mr Pakula told reporters.
"We also think it is important to send a powerful message to the community that if you throw a punch and someone dies you will go to jail.
"If even one offender is put off throwing that punch as a result of this law then it has done an important job."
The offence will carry a maximum penalty of 20 years, the same penalty as manslaughter.
Attorney-General Robert Clark said the new law would result in lesser penalties for one-punch killers.
"Labor's plan is a cop-out for coward punchers because it enables them to be able to avoid responsibility for what they have deliberately inflicted as a dangerous act on their victims," he told reporters.
"The appropriate charge for those who set out to deliberately hit an innocent victim should be murder or manslaughter as it currently is."
Mr Clark said the government was committed to tougher penalties for coward punchers, but wanted to look at the issue carefully before making and decisions.
The assault causing death offence will be introduced in Labor's first year of government.