Controls and audits
Revenue leakage: what audit offices have found
Short answer
- Tanzania, FY 2024/25
- 23 LGAs, TZS 6.65 billion collected outside GoT-HoMIS 1
- Tanzania, prior year
- 12 LGAs, TZS 3.74 billion outside the system 1
- Sierra Leone, 2024
- Judiciary balance of NLe4,216,916 not banked 2
- Nigeria, 2019 audit
- About NGN 125 billion Customs revenue not paid in, as reported by The ICIR 3
- Zambia, 2024 audit
- K4.39 billion in tax liabilities unpaid to ZRA, as reported by Zambia Monitor 4
Tanzania: collection outside systems
The Controller and Auditor General's information systems report for FY 2024/25, dated 30 March 2026, said 23 local government authorities collected non-tax revenue of TZS 6.65 billion from health facilities outside the approved GoT-HoMIS system 1. The year before, 12 authorities collected TZS 3.74 billion outside it 1. The report linked this to weak enforcement and supervision and named the risk of revenue leakage and loss of public funds 1.
The report said core business functions were still manual in 30 entities 1. It named billing systems at several public bodies that were not integrated with the Government e-Payment Gateway 1.
Sierra Leone: revenue not transferred or not traced
- Revenue of the SLRSA and the SLEWRC, NLe1,545,648 and NLe2,244,090, was not transferred to the Consolidated Fund 2.
- Of NLe8,215,736 recorded in the Judiciary's system, NLe3,998,820 was deposited, leaving NLe4,216,916 not banked 2.
- Passport payments of NLe864,994 could not be traced to the designated Immigration treasury account 2.
- Of US$1,843,163.81 collected at the Washington DC embassy from 2022 to 2024, US$205,000.00 was transferred 2.
Nigeria and Zambia, as reported by the press
As reported by Olugbenga Adanikin of The ICIR on 8 January 2022, the Auditor-General for the Federation's report for 2019 said the Nigeria Customs Service did not pay about NGN 125 billion of internally generated revenue into the consolidated revenue account 3. The article said 14 other establishments did not remit NGN 1.28 billion 3. The ICIR article carried no response from the agencies named 3.
As reported by Augustine Sichula of Zambia Monitor on 3 October 2025, Zambia's Auditor General's report for 2024 found K4.39 billion in tax liabilities unpaid to the Zambia Revenue Authority. It found K1.32 billion in outstanding ground rent at the Ministry of Lands and Natural Resources 4.
Findings at a glance
| Country | Auditor | Period | Finding |
|---|---|---|---|
| Tanzania 1 | Controller and Auditor General 1 | FY 2024/25 1 | TZS 6.65 billion collected outside the approved system 1 |
| Sierra Leone 2 | Audit Service Sierra Leone 2 | 2024 2 | Land revenue of NLe3,541,598 not paid into the transit account 2 |
| Nigeria 3 | Auditor-General for the Federation 3 | 2019 3 | About NGN 125 billion Customs revenue not paid in 3 |
| Zambia 4 | Auditor General 4 | 2024 4 | K177.9 million in revenue arrears not collected 4 |
How audits fit the PEFA framework
PEFA indicator PI-30 covers external audit, including audit coverage and standards, submission of reports to the legislature, follow-up and the independence of the supreme audit institution 5. PEFA dimension 20.3 scores how often revenue bodies reconcile collections and transfers to the treasury 6.
Common questions
What is revenue leakage?
Tanzania's auditor uses the term for the risk of revenue loss where collection is manual or outside approved systems 1.
What does "not banked" mean in an audit report?
Cash recorded as collected but not deposited. Sierra Leone's Judiciary had NLe4,216,916 not banked in 2024 2.
Do agencies respond to these findings?
Responses appear in full audit reports. The ICIR article on Nigeria's 2019 report carried none 3.
Which PEFA indicator covers external audit?
PI-30 5.
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Sources
- National Audit Office of Tanzania: Annual Report of the Controller and Auditor General on the Audit of Information Systems, FY 2024/25 (30 March 2026)
- Audit Service Sierra Leone: Graphic Summary of the Auditor-General's Report 2024 (posted April 2026)
- The ICIR, Olugbenga Adanikin: Under Buhari's Watch: Customs failed to remit N125bn into national treasury in 2019, Audit report (8 January 2022)
- Zambia Monitor, Augustine Sichula: Zambia: Auditor-General's 2024 report reveals billions lost to irregularities in public accounts (3 October 2025)
- PEFA Secretariat: Framework for assessing public financial management, PEFA 2016 (2016)
- PEFA Secretariat: PI-20 Accounting for revenue, PEFA 2016 framework (accessed 24 October 2026)
Related
- Reconciliation of government revenue
How governments match bills, bank payments and treasury records, the PEFA timing standards for reconciliation and what audit offices found.
- Bank collection agents for government revenue
How commercial banks collect taxes and fees for governments, how fast they must pass the money on, how they are paid and what audits check.
- Tanzania: the Government Electronic Payment Gateway (GePG)
How Tanzania's GePG works: who runs it, the 2017 legal mandate, how payers use a control number, and what the Controller and Auditor General found.
- Nigeria: the Treasury Single Account and Remita e-collection
How Nigeria's federal Treasury Single Account works, the role of the CBN and Remita, the fee dispute, and what parliament and the Auditor-General found.
- Zambia: the Government Service Bus, ZamPortal and payment gateway
How Zambia collects fees through the Government Service Bus, ZamPortal and ZamPay: who runs them, payment channels, collections and audit findings.