Dame Karen Poutasi has resigned as chairperson of Te Whatu Ora - Health New Zealand.
She has been in the role since 1 July last year, replacing Rob Campbell, who was dismissed for breaching public service neutrality rules when he criticised the National Party.
Health Minister Shane Reti said he has asked Dame Karen to stay in the role until the end of May to give him time to find a replacement.
"Dame Karen has been a valued member of the board since the establishment of Health New Zealand, before stepping into the chair role," he said in a statement.
Dr Reti said Dame Karen's deep understanding of the sector had been invaluable during the establishment of Health New Zealand.