Public servants responsible for the transition between governments failed to support new ministers as no-one had planned for a full scale, new administration.
Officials were caught on the hop after last year's general election, having planned for change no greater than a Cabinet reshuffle - that caused problems like being unable to supply laptops and mobile phones and a lack of experienced staff for incoming ministers.
Acting Ministerial Services Minister Chris Hipkins ordered the review after frustration about the level of staffing and administration support ministers received from Ministerial and Secretarial Support Services (MaSS) upon taking office.
The KPMG report, obtained by RNZ under the Official Information Act, found there was a shortage of skilled ministerial staff and IT support, which "affected some ministers' ability to get their offices up and running in a timely way".
There were "significant issues" with providing basic equipment like laptops and mobile phones, which the report said had a "significant impact on the ability of the ministerial offices to operate efficiently".
It said the funding for any change was based on a "medium-sized Cabinet reshuffle" and that "set the tone for the level of planning required".
The report listed a number of factors including a "lack of strategic governance" within the Department of Internal Affairs and other key agencies, and no "apolitical process" for engaging with political parties ahead of elections to discuss what they might need if they ended up in power.
It also acknowledged the work and commitment of MaSS staff and noted they appeared to be "under-resourced to deal with the volume of work" that came with the new government.
As a result of a 2016 restructure which led to the loss of some "key" staff, "most MaSS staff had not experienced a full change of executive before", the report said.
It found outgoing staff had a "relatively smooth transition" but those coming in felt "let down" by MaSS.
"Staff felt pressured to signing contracts without having sufficient time to seek independent advice and to negotiate contract terms" and that "staff displayed a high level of frustration and distrust with MaSS and DIA as their employer".
Recommendations included a governance group to plan between elections, detailed 'scenario planning' covering the full range of options, making sure there is continuity of skilled staff, and a transition period for the set-up of ministerial offices.