The Department of the Prime Minister and Cabinet (DPMC) was formed as a result of a report that recommended establishing structures to provide two separate streams of advice to the Prime Minister.
These streams were a new government department (DPMC) to supply impartial, high quality advice and support to the Prime Minister and Cabinet; and a Prime Minister's Private Office (which is not part of DPMC), to provide personal support and media services, and advice of a party political nature.
DPMC was established on 1 January 1990. Government House was included in the scope of the department in August 1990, after a review of the Governor-General’s support requirements. The External Assessments Bureau (now called the National Assessments Bureau) became part of DPMC on 1 July 1991.
The Ministry of Civil Defence & Emergency Management (MCDEM) became a business unit within DPMC in April 2014. The National Emergency Management Agency (NEMA) was established on 1 December 2019, replacing MCDEM. The National Emergency Management Agency is an autonomous Departmental Agency hosted by DPMC.
The Canterbury Earthquake Recovery Authority (CERA) became a departmental agency within DPMC in February 2015. On 1 March 2016, to coincide with the wind down of CERA, a new business group - the Greater Christchurch Group (GCG) - was formed to focus on the ongoing regeneration of Christchurch and support the transition of leadership from central government to local institutions. CERA was disestablished on 18 April 2016. The GCG concluded its critical work and was disestablished on 29 January 2021.
The Child Wellbeing and Poverty Reduction Group became a business unit of DPMC in February 2018. It was established to support the Prime Minister as the Minister for Child Poverty Reduction and to support the development of New Zealand's first Wellbeing Strategy for children and young people.
On 1 July 2020 the COVID-19 Group was established as a business unit of DPMC. It continues the work of the National Crisis Management Centre following the centre's deactivation on 30 June 2020. The unit is mandated to coordinate, and where necessary lead, the All-of-Government response to the ongoing pandemic.
The Health and Disability Review Transition Unit was established in September 2020 following consideration by Cabinet of the Health and Disability System Review/Hauora Manaaki Ki Aotearoa Whānui. The Unit leads the response to the Review, including developing the policy response and design of the system operating model, providing advice on the establishment of new entities and legislative change and producing an overall implementation plan and work programme.
In late 2020, Cabinet agreed to establish an Implementation Unit located in DPMC and it began operation in June 2021. The Unit’s purpose is to ensure the Deputy Prime Minister, responsible ministers, Cabinet, responsible public servants and central agencies know, accurately and regularly, whether selected priority programmes are on track to deliver their intended outputs and benefits in the intended timeframes. If they are not, the Unit works with the responsible minister and agency to identify what actions are needed to get the programme back on track and follow up to ensure these actions are taken.
In December 2023, the National Security Group split into two groups. The first retained the name National Security Group and had a focus on national security policy, assessments and core issue coordination. The second group was called the Risk and Systems Governance Group and focused on leading the National Risk Framework, strategic crisis management, and governance of the National Security and Hazard Risk system.