Labour says if elected it might take a look at bail laws in order to fulfil its promise to cut the prison population by 30 percent over the next 15 years.
More than 10,000 people are behind bars in New Zealand - the highest level ever, and Labour has pledged to reduce that number.
Its corrections spokesperson and deputy leader, Kelvin Davis, told Newshub's The Nation one way of doing this could be to liberalise bail laws.
"We have to have a look at them ... there's no doubt that the Sentencing Act in 2002, bail laws, they all contributed to the increased prison muster."
Mr Davis would not definitively commit to a review, but said it was important to figure out where increases to the prison population were coming from.
National Party leader Bill English said while bail laws had perhaps been enforced more strictly than intended, his party did not support winding back sentences.