For the ATO's Progress report No 7 on return processing, showing figures as at 10 September 2010, go here
In relation to fraudulent or overclaimed refunds, the progress report states:
"This year we expanded our use of risk models to help detect potentially overstated or fraudulent claims for refunds which has added two days to the processing time for all returns.
So far, we have identified over 19,000 returns worth more than $84 million which we believe to be potentially fraudulent or include overstated refund claims. Included within these returns is nearly $24 million in claims that are potentially related to identity crime.
Last year 93% of the returns stopped for further review were confirmed to be over-claimed or fraudulent returns."
For more information about known issues as at 13 September 2010, go to Tax time update - 13 September 2010