Hawke's Bay iwi Ngati Kahungunu is the latest tribe to sign an agreement with Child, Youth and Family (CYF) to better protect its tamariki.
Nearly 300 children of Ngati Kahungunu descent were in the custody of CYF at any one time last December.
Social Development Minister Paula Bennett said the agreement marked a commitment to developing a joint plan outlining the support the iwi needed for its children.
A Memorandum of Understanding for child protection was signed in Hastings on Thursday follows similar agreements with Ngapuhi, Ngati Porou and Waikato-Tainui.
Ms Bennett said those agreements had resulted in improved information sharing and greater involvement by iwi in Family Group Conferences, and home visits.
The ministry aimed to incorporate Maori values into work to protect tamariki, she said.
Ngati Kahungunu director of iwi wellbeing strategy, Te Ara Toiora, Jenny Smith said it was about working out the best way to keep mokopuna with whanau or iwi members.
She said the iwi and agency had agreed that mokopuna were best nurtured by whanau, hapu and iwi, and that they would work together to develop whanau-centred solutions.
Cultural needs focus
Meanwhile, a CYF review has found social workers do not always consider the cultural needs of the Maori children they work with.
The agency released the workload and casework document earlier this week, in which it recommended a major overhaul of the role of social worker, with more time spent with vulnerable children.
The year-long review covered several areas including how professionals worked with mokopuna Maori - who make up about half their caseload.
The report explored whether social workers actively sought advice from kaumatua about tamariki and their whanau, despite it not being a formal requirement for staff.
It found there was limited or inconsistent practices which were based on cultural needs but that Maori staff gave cultural support to their peers.
It recommended the agency's cultural systems include procedures to help staff and develop responses to cultural needs.