It could take three years to make changes to the welfare system such as removing excessive benefit sanctions, the social development minister says.
Carmel Sepuloni told TV3's Newshub Nation she was setting up an expert advisory panel to report back before any changes were made.
Beneficary advocates have recently renewed calls for a culture change at the Ministry of Social Development.
Prime Minister Jacinda Ardern has also echoed those views.
However, Ms Sepuloni said the ministry was like a jumbo jet that had been steered for nine years in a certain direction.
Expecting her to undo "nine years of neglect" under the National-led government immediately was unreasonable, she said.
However, the ministry was already making internal changes.