The ATO has advised that the due date for payment for annual PAYG instalments is 21 October 2008. Annual instalment notices will be issued in early July 2008 and agents' clients should be encouraged to pay the full or varied annual instalment before they lodge their income tax returns. When an agent's client’s income tax return is assessed, they will receive a credit for their annual PAYG instalment liability. This will be shown at Label F on the notice of assessment. If their income tax return is lodged before they pay their annual PAYG instalment liability, the client may still need to pay this liability by the due date.
For a copy of the ATO advice, go here