New Zealand police say they arrested 369 people for alcohol-related offending and 291 motorists for drink driving over the weekend in a trans-Tasman blitz on bad booze behaviour.

Operation Unite is the first joint operation of its type between the two countries and the blitz kicked off on Friday night with a new focus on people arriving in town after getting drunk at home.

New Zealand police reported a successful clampdown and they have released provisional statistics for the weekend's operation.

More than 1100 police hit the streets over the weekend. They found 47 licensing breaches, 139 liquor infringement notices issued, 115 assaults and 369 arrests for alcohol-related offending on Friday and Saturday nights.

They also stopped 35,690 vehicles and found 291 drivers over the limit.

The entire operation, including Australian figures, saw 5515 police on the streets, 290 assaults, 550 licensing breaches and 1815 people arrested.

Police have also highlighted the crime numbers they put down to alcohol.

The annual cost of crime due to harmful alcohol and drug use is estimated at $1.1 billion. This includes costs to the victims of crime, the use of police resources, court related costs and prison. Harmful alcohol use cost New Zealand an estimated $5.3b in 2005/06.

Police also said they estimate they spent $306 million or 32 per cent of the police budget on alcohol and drug related offending and issues in 2005/06. On alcohol only, this equalled $172.2m, 18 per cent of the police budget.

At least a third of all police recorded offences in 2007/08 were committed where the offender had consumed alcohol prior to committing the offence.

At least a third of recorded violence offences and family violence incidents in 2007/08 were committed where the offender had consumed alcohol prior to committing the offence.

In serious offending, such as homicides and incidents where force was used by police, about half of the alleged offenders or victims were affected by alcohol.

Police say that on an average day 62 individuals are either driven home or detained in police custody due to their state of intoxication, and 342 offences occur where alcohol was involved in the offending.

In Australia, alcohol-related crime is estimated to cost $2.14b a year, with $944m alone spent on policing.

- NZPA