December monthly activity statement
The due date for lodgment and payment of the December 2012 monthly business activity statement will be extended from 21 January 2013 to 21 February 2013 for small business clients (businesses with up to $10 million turnover) who report goods and services tax (GST) monthly and lodge electronically using a registered agent.
http://www.ato.gov.au/content/00247973.htm