I didn't find anything on wind sock speeds from a search through Australian publications.
I did find that the MOS specification in Australia is for a 3.75 meter white wind sock which matches the FAA Size 2 - Twelve feet (3.75 m) in length and 36 inches (0.9 m) in throat diameter.
according to the "FAA SPECIFICATION FOR WIND CONE ASSEMBLIES"
4.2.6 Windsock Extension. Test the windsock to assure that it extends fully when subjected to a wind of 15 (+2,-1) knots (+3.7, -1.8) km/hr or (+2.3, -1.2 mph).
http://www.faa.gov/airports_airtraff...0_5345_27d.pdf
I also found out that ir's prohibited to export wind indicators to Libia. I couldn't find any phalic references though - some good ones allready posted.