Australia has adopted AHD as height references for the entire continent. Ever since its inception in 1971 many researchers has pointed out problems arisen from AHD. Among the studies touching on this issue were; Holloway R (1988) The integration of GPS heights into the AHD. UniSurv Report S-33, UNSW. Kearsley et al (1988) The AHD - problems and proposals. AS, 34(4):363-380 Kearsley et al (1993) National height datums, levelling, GPS heights and geoid. AJGPS 59:53-88 Featherstone (1998) Do we need a gravimetric geoid or a model of AHD to transform GPS heights in Australia. AS 43(4):273-280 Featherstone (2002) Prospects of the AHD and the geoid model. IAG Vistas for Geodesy, pp 96-101 Featherstone (2004) Evidence of a north-south trend between AUSGeoid98 and the AHD in southwest Australia. SR 37(291):334-343 Featherstone (2006) Yet more evidence for a north-south slope in the AHD. J of Spatial Sci 51(2):1-6 Featherstone (2008) GNSS-heighting in Australia: current and emerging issues. JSS...