The Labour Party says figures just out on the number of people who are no longer receiving benefits leaves it unclear how many people have been moved off benefits and are left to live without income.
Social Development Minister Paula Bennett says beneficiary numbers are at their lowest since 2009.
The minister said over the past three months, 29,000 people have come off benefits.
She said of these, 17,600 people have come off the Unemployment, DPB and Sickness Benefits and into work.
But Labour's social development spokesperson Jacinda Ardern says it's not clear what has happened to the remaining people who have not found work.
"We know for instance that a number will list as having gone overseas to find work, some people will come off the Domestic Purpose Benefit because they've repartnered - but there are certainly cases where we simply do not know where people have gone after they've exited government support."
Ms Ardern says some people have had their benefit cut for failing to turn up to meetings they say they hadn't received a request to attend.
The Ministry of Social Development cancelled 525 benefits in the last quarter after it implemented an enhanced information sharing arrangement with Inland Revenue.
There are now 310,146 people on benefits, including 92,550 sole parents on DPB, 58,208 on Sickness Benefits and 48,756 on Unemployment Benefits.