The Ministry of Justice's plan to make some staff work from home raises security concerns, the Public Service Association (PSA) says.
Its warning follows the ministry's plan to cut about 100 jobs, and have about 100 other staff work permanently from home within the next 13 months.
The affected staff deal with court fines and reparations, and enforce payment when required.
The ministry said most people paid their fines online or over the phone, so collections staff did not need to be in any specific location.
But PSA national secretary Erin Polaczuk said even small things like ergonomic equipment and heating in the houses people worked in needed to be taken into account.
"There are also security of data issues," she said.
"These people deal with private information and we would want to know there are no breaches of privacy issues with members of the public."
Ministry collections staff manager Bryre Patchell said 23 people had been working from home for over two years and this number would grow to 100.
"We have a fully electronic way of working where we push work to staff irrespective of where they are," he said.
"We have had independent assessments of the security requirements of people's homes, and independent assessments of health and safety, and privacy."
Mr Patchell said the information dealt with at home was electronic and incapable of being printed out so it was as secure as it was in the office.