Click the embedded link – this may help:
A copy of the registered strata plan can be purchased from LPI’s approved information brokers.
This info was sourced from here:
https://www.lpi.nsw.gov.au/about_lpi/strata_scheme_questions/strata_scheme_laws
I have also read somewhere that this site may be helpful for accessing strata plans: https://www.saiglobal.com/property/.
If you are in Sydney you could visit their office and perhaps obtain a copy over the counter (for a fee). Contact details are here: https://www.lpi.nsw.gov.au/about_lpi/contact_us