The Auditor-General has found that the system for providing support to government ministers has significant problems.
Lyn Provost's report into the administration of ministerial expenses was tabled in Parliament on Tuesday afternoon.
It finds that there is no pattern of major spending irregularities and only occasional transactions that were clearly, or arguably, outside the rules.
In her report, Ms Provost says she finds the myriad rules, entitlements and procedures covering parliamentary and ministerial spending puzzling.
She is recommending a full review of the legislation under-pinning the administration of ministerial support, and that Ministerial Services revise its financial management policies and procedures.
Prime Minister John Key has indicated both recommendations will be acted on.
However, he says overall, the report finds the financial management processes around ministerial expenses to be sound.