Online Public Access Catalogue, or also known as OPAC, is an online search engine that allows members of the public to search through Internet at anytime and place for library materials from a comprehensive database of bibliographic records called the Union Catalogue, contributed by various participating libraries.

Under the Sarawak State Government initiative, the objective is to enable the sharing of library resources information through the Union Catalogue concept. In order to make these information accessible by the public, OPAC is developed as part of the ANGKASA Library Management System to provide online searching to the public at anytime and place without being constraint by geographical boundry, which indirectly encourage the usage of library materials in the community.

OPAC allows searching of library materials by various access point such as author, title, subject, isbn, issn, publisher, year published, media type and keyword. Users may narrow down their searches to specific library collection too. OPAC also allows users to browse for library collection by author, subject and publisher, which links to the work for these areas. Besides showing the availability of particular library material at various libraries, OPAC also allows registered members to place online reservations if material is not available for check out.

OPAC is accessible online within and outside all participating libraries such as from office and home. To access OPAC, all you need is just an Internet browser installed on your computer which has either SarawakNet or Internet connection. For further information on how you can get connected to the OPAC and use it, you may approach the information counters of the participating libraries for help.