what's going on?, page-27

For posters future references:

"(As the examples have shown fully franked dividends and franking credits make investing in Australian shares a tax effective strategy. However, the ATO realises this and to prevent investors from abusing the system they introduced the 45 day rule. The 45 day rule states that shareholder must hold shares for 45 days (not counting days of purchase or sale) for any franking credits over $5,000.)"

The very interesting part that has to be taken in consideration as well is the $5,000.00 base level ceiling.