Police Minister Judith Collins credits a number of 'get tough' measures including tasers and extra powers for police in lowering crime.
Latest police statistics show overall crime dropped by 5.8% in the year to June 2011.
Ms Collins told Morning Report that more front line police have helped, especially in Counties Manakau, where 300 extra officers were added.
However, Victoria University criminologist John Pratt says the falling crime rate mirrors a decrease in other Western nations.
Professor Pratt told Morning Report the crime rate has been decreasing since the mid-1990s and will continue to do so.
He said New Zealand's ageing population is one of the reasons behind the drop.
Professor Pratt said people are now also taking greater care to make sure their property is secure and are carrying less cash.