Suggested identification a bit of a guess really as it would have been useful to confirm that it had gills and how these were attached to the stem and the colour they were.
My suggestion of Hypholoma australe is based on pictures and description from http://www.fncv.org.au/wp-content/uploads/publications/fungi_in_australia/fia-3-basidio-agarico-I.pdf
I hope this is a correct identification. Page 450-452.