The Instrument of Government (Regeringsformen), which is one of Sweden's constitutional laws, states that Parliament should appoint one or more Parliamentary Ombudsmen and lays down some rules concerning the authority of the Parliamentary Ombudsmen. Chapter 13, Article 6 of the Instrument of Government. Parliamentary control.
The Riksdag Act (Riksdagsordningen) includes more details concerning the authority of the Parliamentary Ombudsmen, their number, how they are appointed, for how long they are appointed etc.
The Act with Instructions for the Parliamentary Ombudsmen (Lag [1986:765] med instruktion för Riksdagens ombudsmän - ”JO-instruktionen”) includes further descriptions of authorities and limitations, clarifications of the task and how the operations should be organised and reported.
Public Access to Information and Secrecy Act (Offentlighets- och sekretesslagen [2009:400]) includes secrecy provisions that apply to the Parliamentary Ombudsmen (JO).