A woman who claims a Work & Income case manager swore at her, has described the circumstances of the incident.
WINZ is investigating the matter, which it describes as serious.
The case was raised in Parliament on Wednesday by Green Party MP, Sue Bradford.
The woman says she visited the WINZ office in Rotorua to organise a food grant, after a case worker arranged to approve the grant.
But she says she was dealt with by a different person who refused her request and swore at her twice, in front of her son.
Also in Parliament: Maori Party co-leader Tariana Turia raised a case in which she said two kaumatua on sickness benefits had their details photocopied by a security guard, and were verbally abused.
Ms Bradford also raised another complaint of bullying by a case worker at the Gisborne office. She said all three cases are not isolated incidents.
Minister for Social Development and Employment Ruth Dyson says Work & Income received only 147 complaints out of 1.5 million interviews.
The head of Work & Income, Patricia Reade, says the department has a range of disciplinary options available, including dismissal, if it is shown the staff member involved acted unprofessionally.