Poverty forces people to steal. Voting national would produce more inequitable outcomes for those with low incomes and increase crime further. Your anecdotal experiences with observing crime does not mean it’s increasing.

If you want the real answer - crime (excl. theft) is not increasing. It’s actually flat.

If you look at actual statistics from policedata (https://www.police.govt.nz/crime-snapshot-0), they’re largely inline with recent historical averages - except for theft - which has an increase.

What causes petty theft? Poverty and desperation.

What causes poverty and desperation? Inequitable government policy - for example: poor housing policy, poor wages.

You say you’ll vote for National. I’m afraid to tell you this will only make it worse. Being “tough on crime” by imposing strict sentences will just lead to higher prison populations and not a reduction in crime.