The Australian Taxation Office (ATO) computer system will be unavailable from 22 January to 27 January 2010. 

The ATO advised that some processing will be suspended in the days leading up to the 22 January and processing will be delayed in the weeks following up until mid February 2010.

All businesses and individual taxpayers expecting a tax refund should aim to have their returns lodged as early as possible to reduce the likelihood of any delays.