New Zealand is generally safe for travelers, but international visitors have been known to get into trouble when they take their safety for granted. Use common sense, particularly if walking around cities at night. Stay in populated areas, and avoid deserted alleys. Although New Zealand is an affluent society by world standards, it has its share of poor and homeless (some referred to as "street kids" if they are young), and violent gangs do exist. Avoid bus and train stations or city squares and parks late at night.
Hotels furnish safes for guests' valuables, and it pays to use them. Don't show off your wealth, and remember to lock doors of hotel rooms and cars. Sadly, opportunist criminals stake out parking lots at some popular tourist attractions. Put valuables out of sight under seats or lock them in your trunk before you arrive at the destination.
Most visitors have no trouble and find New Zealanders among the friendliest people in the world. Nine times out of ten, offers of help or other friendly gestures will be genuine.
Women will not attract more unwanted attention than in most other Western societies, nor will they be immune from the usual hassles. In cities at night, stick to well-lighted areas and avoid being totally alone. Hotel staff will be happy to give tips on any areas to avoid, and the times to avoid them. New Zealand is relatively safe for women, but don't be complacent. Female travelers have been victim to sexual assault in New Zealand; hitchhiking is not recommended, especially for solo females.
Some top Kiwi destinations have accommodations especially geared to women. Wellington, for instance, has a women-only guesthouse, and the Base Backpacker hostel chain (stayatbase.com), with locations in major New Zealand cities, created Sanctuary Floors, secure women-only zones with special amenities.
Transportation Security Administration (TSA) (www.tsa.gov.)
Australian Department of Foreign Affairs and Trade (www.smartraveller.gov.au.)
Consular Affairs Bureau of Canada (www.voyage.gc.ca.)
U.K. Foreign & Commonwealth Office (www.fco.gov.uk.)
U.S. Department of State (www.travel.state.gov.)