Data released by Statistics New Zealand show 19 people were convicted in the Masterton District Court for obtaining benefits by deception - a threefold increase over the six who were convicted in 2013.
Associate Minister for Social Development Jo Goodhew said the ministry had stepped up efforts to reduce benefit fraud.
"Over the past two and a half years around 9500 benefits have been cancelled after fraudulent and illegitimate payments were discovered," she said.
"These changes hold people to account for their actions, and make it difficult to defraud the welfare system."
A vast majority of the fraud has been identified through increased information sharing with Inland Revenue - making it easier for the Social Development Ministry to identify clients who under-declared their incomes, which would have affected benefit payments.