Inland Revenue has confirmed details of a major restructure after closing early today.
The Public Service Association, the union that represents government workers, said it has "serious concerns" for staff after IRD announced its final decision document on its proposed business transformation, which the union believes could affect up to 4000 staff in the organisation.
"The final decision document - which provides little transparency regarding possible reductions in staffing levels - indicates that organisational changes will be made from February 2018, with the rollout of Stage 2 of IRD's computer system changes beginning just 2 months later," said PSA spokeswoman Erin Polaczuk.
"The loss of expert staff and the lack of certainty for workers reapplying for more simplistically modified roles means that important regulatory changes to the tax system rest on very shaky foundations," Polaczuk said.
"This could affect up to 4000 staff in varying ways at this stage of the restructure, and this has not been fully explained," she said.
Polaczuk said the PSA understood there would be a reduction of around 25-30 per cent of staff by 2021.
IRD said there would be no reduction in the frontline services staff in the organisation. Commissioner Naomi Ferguson said 3300 customer-facing staff would all be "offered new roles or confirmed straight into new roles".
A spokesman for the government organ said those who are not confirmed straight into new roles may have to go through an application process.
IRD has also added 18 specialist positions across the organisation.
IRD shut its offices four hours early today and closed its call centre for more than two hours so staff could hear about changes at the organisation.
The government department, which employed 5789 people as at June last year, said members of the public could still sort their tax affairs online or use its automated phone service during this time.
"Inland Revenue is closing some services today so that all of its staff can hear about changes to the organisation. Contact centres will be closed from 12.45pm to 3.30pm. Offices will close from 1pm until the end of the day," IRD said in a statement today.
In March last year, IRD announced it would cut 1500 jobs "across the board" between 2018 and 2021. It said the workforce would shrink by 25-30 per cent.
The transformation plan is part of a $1 billion-plus modernisation of the tax system and the biggest change to the system in 25 years.
An IRD spokesman could not be immediately reached for comment.