Tasmania has tightened laws around one-punch attacks, removing a 'loophole' which the government says previously allowed offenders to escape manslaughter convictions.
Amendments to the Criminal Code Act 1924 and Sentencing Act 1997, which passed state parliament in March, came into effect on Wednesday.
The reforms close a loophole which had allowed offenders to avoid a manslaughter conviction if they successfully argued the death of a victim was an accident, Attorney-General Elise Archer said in a statement.
"These changes make the defence of 'accident' much clearer and ensure the excuse of 'being intoxicated' (being under the influence of alcohol or drugs) cannot be used for random acts of violence," she said.
"These reforms will send a strong message that senseless and cowardly acts of violence will not be tolerated."
Ms Archer said a number of other offences in Tasmanian legislation capture one-punch incidents such as assault and grievous bodily harm.