Indonesian legislation can easily be obtained in Indonesian through various government websites. However, finding English translations is difficult. The following may be of some assistance:
The Indonesian legislative branch is the People’s Consultative Assembly (Majelis Permusyawaratan Rakyat or MPR), which consists of two houses of parliament: the lower house is the House of Representatives (Dewan Perwakilan Rakyat or DPR), and the upper house is the Regional Representatives Council (Dewan Perwakilan Daerah or DPD).
Laws (Undang-Undang) are drafted by the parliament (Dewan Perwakilan Rakyat or DPR) with the President’s consent. In the event of emergency, the President can immediately enact a Government Regulation in Lieu of Law (Peraturan Pemerintah Pengganti Undang-Undang or Perpu), which shall be subject to an immediate review by the DPR.
By virtue of Article 24C section (1) of the Constitution, Laws, and Regulations in Lieu of Laws are subject to constitutional review by the Constitutional Court, which can test legislation for constitutionality.
For detailed information on the legislative / law making process (including the role of the Constitutional Court), see the open access publication by S H Febrian, Handbook on the Legislative Process (published by the DRP and UNDP).
See also 'Law-Making' on the House of Representatives (DPR) website for a brief explanation.
For scholarly commentary, see 'Indonesian Laws and Lawmaking' - chapter 2 in the following book:
The Indonesian Ministry of State Secretariat (Sekretariat Negara Republik Indonesia) produces the State Secretariat Index of Legal Products. Select UU or Undang-Undang for Act/Law. To browse, select the relevant year to see a list of the entire acts/laws passed by the parliament (DPR) in that particular year. In Indonesian only.
The hierarchy of rules and regulations in Indonesia is outlined under Article 7 of Law No. 12 of 2011 on the Formulation of Law and Regulations (link to unofficial translation):
In addition to the legal instruments above, there are Presidential Instructions or Decrees, Ministerial Decrees and Circulation Letters, which add further detail to Laws and Government Regulations.
The Foreign Law Guide (UniMelb staff & student access) lists Indonesian laws alphabetically by topic, and provides information on where to find the laws, linking where possible to open access online sources. However, while the Foreign Law Guide is written in English, very few of the laws are available in English. All are available in Indonesian and many in Dutch. Note also that the Guide has not been updated since 2013.