Neighbours should keep an eye on the mailboxes of vacant houses for any parcels or packages delivered there, Detective Senior Sergeant Malcolm Inglis said.
There had been a sharp increase in internet importation of drugs such as methamphetamine throughout the country and getting mail delivered to unoccupied homes was one option chosen by drug importers.
Usually the home owners were unaware of the delivery, he said.
The increase in this type of offending was usually by locals rather than out-of-towners.
Drug dealers came from all walks of life and the hard drugs were being imported from around the world - from China, Europe, the Netherlands and Germany in particular, and from the United States and Canada, Det Snr Sgt Inglis said.
''It's certainly of concern that the amount of methamphetamine we're finding is continuing to rise. We're trying to prevent it getting here as much as we can.
''It's a particularly bad drug and creates crime in its wake.''
Last month police intercepted four packages destined for unoccupied holiday homes in the Clyde area. Four packages containing about $200,000 worth of MDMA (ecstasy) were intercepted after entering the country.
Waitaki MP Jacqui Dean said there was no doubt hard drugs were entering the local community ''but that doesn't mean that we have to sit back and accept it''.
''Keeping hard drugs out of Central Otago towns is the joint responsibility of the Government, local police and the community and I call on everyone to be proactive in stopping this problem,'' she said.
Five people were arrested and charged with drug offences after police searched properties in Queenstown, Alexandra and Wanaka last week.
The people, aged between 21 and 46, were facing a variety of charges including the supply of methamphetamine and the distribution of cannabis, Det Snr Sgt Inglis said.
However, the arrests were not linked to three Central Otago people charged last month with drug-related offences. A Cromwell man was arrested and charged with allegedly importing an estimated $200,000 of MDMA.
A Clyde man was facing charges of importing and selling methamphetamine, and cultivation of cannabis, while a Clyde woman had been charged with cultivating cannabis.
