The number of people waiting for follow-up hospital outpatient appointments in Wales has increased substantially since 2015, according to a report by the Auditor General for Wales.
The Auditor General says urgent action is needed with the number of patients waiting twice as long as they should be increasing by 55% to around 200,000.
The report calls for a reduction in the number of patients experiencing delays and for health boards to get better at assessing and managing the risks to patients.
The Welsh Government says it's working to make improvements and has commissioned the Outpatients Steering Group to support local health boards secure improvements.
Shadow Health Secretary Angela Burns AM said the Welsh Government "has to wake up and recognise the desperate need for change".