[en] Nuclear medicine centres in Australia and New Zealand were surveyed in 1998 on behalf of the Australian and New Zealand Society of Nuclear Medicine (ANZSNM) and the Australasian Radiation Protection Society (ARPS) in order to establish diagnostic reference levels. A survey form was mailed to all centres, requesting information on the usual radiopharmaceutical activity administered to a standard adult patient and how the activity is calculated for children. The overall response rate was 89.5%. Data was obtained for 80 imaging procedures and 17 non-imaging tracer studies. For the 68 procedures for which data was available from 10 or more centres, the Most Common Activity and the Reference Activity were found from the mode and 75^th percentile of the distribution of activities. A follow-up survey of the 8 hospital centres specialising in pediatric nuclear medicine in Australia was conducted in 1999-2000. Data on the maximum and minimum administered activities (A_max and A_min) was obtained for 43 pediatric imaging procedures. A_max values were significantly less than the Reference Activities determined for adults. The median values of A_max and A_min are recommended as Pediatric Reference Activities. The effective dose from the Reference Activities was calculated for adults (male and female) and children. The survey results are available on the ANZSNM and ARPS web sites at http://www.anzsnm.org.au and http://www.arps.org.au. (author)