Justice advocates say the Government is unnecessarily pouring money into building new prisons, in the 2017 Budget released on Thursday afternoon.
The advocates say increasing the number of prison beds simply means an increase in the number of prisoners.
"Avoidable" and "unnecessary" were a few of the words used.
The Budget includes $763.3 million for increasing prison capacity and an additional $255 million in operating funding.
A fraction of that has been allocated for prisoner rehabilitation - $30 million over four years for alcohol and drug treatment, education, treatment for violent offenders and reintegration support.
Another $13.9 million over the next four years will go toward reducing reoffending, targeted at high risk young offenders.
Justice advocates contacted by Newshub were in agreement that increasing the capacity of prisons would mean an increase in the number of prisoners.
Justice Advocacy group Just Speak says the Budget is supposed to be about vulnerable children, but expanding prisons will just see those vulnerable children locked up.
"You can see from the way the funding is prioritised that it is mostly about increasing prison beds and increasing police numbers and far less around actually supporting people to change their lives around."
"This is a Budget very much focused on vulnerable children, but at the same time they are also expanding prison cells for these children who fall through the cracks," spokesperson Katie Bruce told Newshub.
There is no question that by expanding prisons, numbers of prisoners will increase, she said.
"We will absolutely see more prisoners if we build more prison beds. That's what we see in every other country that's done the same thing."
The money would be better spent in the community, Ms Bruce said in a comment echoed by researcher Kim Workman and abolitionist prison organisation No Pride in Prisons.
The Government's need to expand prisons amidst falling crime rates indicates a failure of policy, Ms Bruce said. She pointed to changes to bail laws introduced in 2013.
The Bail Amendment Act 2013 meant serious offenders, including young, repeat offenders, would have to meet a higher bar to be granted bail. The Bill was opposed by the just 19 members of Parliament - the Greens, the Māori Party, Mana and Brendan Horan.
The Bail Act was also singled out by Mr Workman, research associate at the institute of criminology at Victoria University, who said the $763.3m budget for expansion of prisons is "totally unnecessary" and "hardly social investment."
Mr Workman said there were a couple of simple things the Government could do to decrease the prison population: Revoke the Bail Amendment Act and the three strikes policy, increase social services and invest in mental health.
"I think it's totally avoidable. We don't need to be spending $1 billion on prisons. We should be spending that money on social housing or mental health."
Mr Workman said the Government is sending so many people to prison that they can't provide essential rehabilitation services.
"A fraction of the money is being spent on rehabilitation in the Budget. We need to stop thinking the only way to provide rehabilitation is in the prisons. We need to think more about providing programmes that are community based setting up residential drug and alcohol treatment centre.
"Instead of immediately taking a punitive criminal justice approach to social stress, we should be looking at more of a social response," he said.
Prison abolitionist organisation No Pride in Prisons said the Government would do better to invest in housing, education and healthcare.
"The more than $1 billion spent on prisons is an insult to the thousands of people living in poverty in this country, as well as the more than 10,000 people in prison today," the group's spokesperson Emilie Rākete said in a statement.
"Pumping money into the prison system is simply throwing money away."
She said the group expects to see the prison population continue to rise in the coming years.
The Government has set aside $1.1b over four years for schools and early childhood centres, $803m for other social services, including social housing, getting people into employment and Ministry for Vulnerable Children, and $321m for cross-agency social investment programmes.
"To support Corrections to deliver its core services and reduce reoffending, Budget 2017 will set aside $255.9 million of operating funding over four years and $763.3 million in capital funding for more prison capacity," Corrections Minister Louise Upston said in a press release.
"While we're focused on reducing offending, we also want to ensure we have enough prison beds to keep the worst offenders off our streets," Ms Upston said.