The complaints registered against healthcare providers and other public bodies will now be available online for the first time.
The Parliamentary and Health Service Ombudsman has launched a website where summaries of investigations into companies can be read.
People will be able to search by the name of the organisation, by complaint handling issue (e.g. unnecessary delay) or by what the complaint was about (e.g. sepsis).
Current complaints on the website relate to investigations carried out in February and march.
Of the 81 cases, 58 were healthcare related, and 23 involved Parliament.
Among healthcare cases, two were about Barking, Havering and Redbridge University Hospitals NHS Trust; two were about Norfolk and Norwich Hospitals NHS Foundation Trust – one of which involved the hospital misinterpreting a scan of a patient with lung cancer; and one involved Barts Health NHS Trust.
Parliamentary and Health Service Ombudsman Julie Mellor said: "For the first time MPs, members of the public and service providers will be able to go online and see the types of complaints we have investigated.
“We are modernising the way we do things so we can help more people with their complaints and to help bodies in jurisdiction learn from mistakes other organisations have made to help them decide what action to improve their services.
“We will continue to work with others including consumer groups, public service regulators and Parliament, using the insight from our casework to help others make a real difference in public sector complaint handling and improve services.”
The Parliamentary and Health Service Ombudsman is the final step for people who want to complain about being treated unfairly or receiving poor service from the NHS in England, or a UK government department or agency. It investigated 2,199 cases in 2013/14 compared to 384 the previous financial year.