The Auditor General for Wales is the auditor of the National Assembly for Wales and its sponsored and related public bodies including the NHS in Wales. He also has responsibility to appoint auditors to act as watchdogs of local government. They formally audit the accounts of local authorities and produce value-for-money (VFM) reports to help them to improve their services. These appointed auditors also audit councils' annual improvement plans.

Public audit is far broader than that carried out in the private sector and places highly demanding duties and responsibilities on the auditors. The WAO takes this into account when deciding on the appointment of auditors to any local authority or NHS body. The WAO has currently appointed in-house auditors or auditors from PricewaterhouseCoopers, KPMG and Deloitte and Touche, all approved private accountancy firms, to undertake audits in Wales.

The WAO keeps the selection of audit appointments under review and carefully monitors auditors' performance through its annual programme of quality control reviews.