Beneficiary groups have slammed Work and Income over a new report showing people missing out on $200 million a year in entitlements.
Beneficiary advocacy groups say figures released under the Official Information Act paint a damning picture of the government and Work and Income.
According to the figures, there could be $200 million or more in payments not being collected by beneficiaries.
Auckland Action Against Poverty spokesperson Alastair Russell said Work and Income case managers deliberately withhold information about benefit entitlements.
"There's a whole raft of entitlements that people both in and out of work are entitled to and Work and Income treat them like state secrets.
"If you don't ask, you don't know. And you don't know what you don't know."
Mr Russell accused Work and Income of holding back information from clients about their rights, and Kay Brereton of the Beneficiary Advocacy Federation agreed.
"They're missing out because they're not being told about it."
She said people coming off benefits often did not realise they might still be entitled to WINZ payments.
"There's very poor exit processes at the moment and that's part of why they're missing out.
"I think it falls to the case managers because they're the ones who are supposed to know the rules, beneficiaries can't know the rules."
She said the people who were missing out were those who needed it most.
"We're talking about low income earners with high rents or high disability costs who could be getting that help."
Information released by the Ministry of Social Development lists childcare assistance, disability allowances and accommodation supplements as particular benefits which people find difficult to access.
The Ministry of Social Development said people often cannot make appointments or may find the work required to access benefits as too much hassle.
Social development minister Anne Tolley said her staff did not withhold money, but she accepted some of the report's findings.
"I agree at times it's too bureaucratic and we're doing our best," she said.