It has been reported that form the 1 July 2013 the 457 visa application fee will increase from $455 to $900. See article:
http://www.abc.net.au/news/2013-05-14/nrn-fedbudget-457costs/4689874
Labor has plans for Radio Adverts to Promote a Crackdown on 457 Visas. See article:
http://www.afr.com/p/national/labor_ads_to_promote_work_visa_crackdown_35rbIW85h1LS1vpVSYOs6I
This will be at same time as ATO Investigations of 457 Visas. See article:
http://www.workvisalawyers.com.au/news/entry/student-visa-and-temporary-work-visa-holders-are-you-currently-being-investigated-for-tax-fraud-.html