Career public servant Debbie Power has been appointed chief executive of the Ministry of Social Development.
Currently the Deputy State Services Commissioner, Power will take up her new role in early February next year.
Current chief executive Brendan Boyle steps down at the end of this year.
Power started her public service career in 1980 as a frontline case manager at the Department of Social Welfare, now the Ministry of Social Development (MSD).
As chief executive, she will head a department of around 6900 staff and oversee an annual budget of about $25 billion.
"Power is a seasoned public servant and a proven leader. She is compassionate and determined and able to engage staff around a sense of service and purpose.
"It is a privilege leading a ministry that plays such an important role for New Zealanders, and I have no doubt her leadership will ensure that the ministry delivers accessible, fair, and transparent services," State Services Commissioner Peter Hughes said in a statement.
Power's appointment comes as MSD undergoes a culture change.
All of Work and Income's service centres will undergo a $2.5m transformation from cold, clinical waiting rooms into colourful, well-furnished spaces as part of the Government's plan to make the welfare system "kinder" and less punitive.
"It's the right thing to do," Social Development Minister Carmel Sepuloni has said.
"We don't want to be pushing people into further hardship or causing unnecessary stress and anxiety in people's lives because we're making it difficult for them to access something that they are actually eligible for."
MSD also said last month it would stop using fake names and signatures when dealing with "high risk" clients, after a court ruling found the behaviour was illegal.
The Social Security Appeals Authority said it warned Boyle that the practice was unlawful but he continued to support it for staff safety reasons.
Boyle is also among those being sued by Deputy Prime Minister Winston Peters over the leaking of information about his superannuation.
Hughes has previously said that it was always Boyle's intention to step down at the end of his term in December.