EN 15194 is the European standard for electric bikes and was adopted in Australia in 2012. Amongst other things EN 15194 allows for a 250 W motor. There is quite a bit to this standard and if someone claims that their bike is to this standard ask to see the independent Verification to EN 15194 Compliance or a copy of the import approval from The Department of Infrastructure and Transport. This standard does not allow a throttle except for a feature allowing 6 Kph (walking speed). If an e-bike is 250W and has a throttle the throttle must only be capable of taking the bike to walking speed.
For more on EN 15194 Google it or for an article that gives a good outline we like the one on the following link: http://www.pedelecs.co.uk/forum/electric-bicycles/3946-new-epac-standard-en-15194-safe-e-bikes.html