The law and order portfolio is one of the most politically charged where common terms include "dog-whistle politics", "knee-jerk reactions" and "soft on crime".
In the past term the Government has reformed the justice sector, with a particular focus on improving victims' rights.
But it has also courted controversy for trying to tamper with the courtroom principle of the right to silence, for passing the three-strikes law for repeat offenders and stripping prisoners of the right to vote.
The main plank of National's law and order policy this election is similarly controversial. It is proposing the indefinite detention of the country's worst offenders who are at a high risk of reoffending.
If a High Court found that risk to be imminent, the offender would be transferred to a secure civil detention centre after finishing their sentence, and would remain there until the Parole Board deemed them safe for release.
The Corrections Department believes it would affect five to 12 offenders a decade.
National's law and order spokeswoman, Judith Collins, wants to push it through, even if it contravenes the Bill of Rights Act, arguing that she would rather that than picking up the pieces of a horrible crime from an offender that the state had no option but to release.
The party also pushed through the three strikes law despite questions raised about inconsistencies with the Bill of Rights.
This is in line with National's approach over the past three years: harsh policies for the worst offenders, while taking it easier at the lower level and ramping up rehabilitation treatments in prisons, including more programmes to fight addictions, improve numeracy and literacy and for work-to-release opportunities.
The policing excellence programme National has presided over includes greater visibility of police and a country-cop approach to low-level offending. The rationale is that a night in the cells would send just as good a message as trudging them through the court system.
Act wants to punish all low-level offending to send an unequivocal message that all crime will not be tolerated. Labour wants to treat petty crime seriously on the basis that it often leads to more serious crimes, although this appears to counter its justice policy for police diversion for minor offences committed under the influence of alcohol or drugs.
Labour also wants to bring in a Sentencing Council with a view to eliminating prison sentences of less than six months and putting the savings towards prisoner rehabilitation.
Labour also plans to double the number of cops at the 62 one-cop stations around the country, as part of 145 extra constables over four years at a cost of $96 million, a policy applauded by the Police Association.
Labour's law and order spokesman, Clayton Cosgrove, has said the party would likely scrap the three-strikes law. The Maori and Mana parties want it gone.
The Maori, Mana and Green parties support a judicial system inclusive of the principles of Maori justice to tackle the disproportionate number of Maori in prison.
The Maori Party also wants its reintegration houses called Whare Oranga Ake established in every prison.
A challenge to all parties is how to implement their policies without any expectation of new money in the sector.