The following I found in Wikipedia. So, to this day ‘High Speed Rail’ does not exist yet in Australia!
Based on the definition of a minimum top speed of 200 km/h in passenger service, High-speed rail in Australia does not yet exist, but there are proposals for high-speed rail (HSR) infrastructure in Australia (also known as very fast train projects) – several proposals have been investigated since the early 1980s.
Various combinations of the route between Melbourne, Canberra, Goulburn, Sydney, Newcastle, Coffs Harbour, Gold Coastand Brisbane have been the subject of detailed investigation by prospective operators, government departments and advocacy groups.
Phase 1 of the A$20m HSR study was released on 4 August 2011. It proposed a corridor similar to the 2001 study, with prospective stations located in Melbourne, Tullamarine, Albury, Canberra, Goulburn, Sydney, Newcastle, the Mid—North Coast, Gold Coast and Brisbane. The cost for this route was estimated at A$61 billion, but the adoption of more difficult alignments or cost blowouts could raise the cost to over A$100 billion. The report urged the authorities to acquire land on the corridor now to avoid further price escalations.
Work on phase 2 of the study started in late 2011 and culminated in the release of the High speed rail study phase 2 reporton 11 April 2013. Building on the work of phase 1, it was more comprehensive in objectives and scope, and refined many of the phase 1 estimates, particularly demand and cost estimates.
Less ambitious proposals have included a minor 9.2-kilometre (5.7 mi) Jindalee Deviation mentioned in a 2006 Ernst and Young Report. Naturally a slow evolution consisting of many short deviations which can provide benefits sooner will not be equivalent to a few large deviations which could provide bigger bypasses and greater benefit. However more ambitious proposals come with greater risk of projects being delayed or cancelled.
Over the years a number of deviations have been proposed for the track between Junee and Sydney, including between Glenlee and Aylmerton (known as the Wentworth Deviation), Werai and Penrose, Goulburn and Yass (Centennial Deviation), Bowning and Frampton including a bypass of Cootamundra (Hoare Deviation), and Frampton and Bethungra (removal of the Bethungra Spiral). The proposals would replace 260 kilometres (160 mi) of winding track with 200 kilometres (120 mi) of straighter, higher-speed track, saving travel time, fuel, brake wear and track maintenance. However the Australian Rail Track Corporation have only documented plans for a handful of minor deviations to be completed by 2014.