Victims of Australia's crippling bushfires can have cash burnt in the blazes replaced by putting the destroyed banknotes in a plastic bag labelled 'bushfire' and taking it to a local bank.

The Reserve Bank of Australia (RBA) is helping victims who may have had cash stored on their property, even if it was completely destroyed.

The RBA has asked victims to collect any banknote debris they could find from the wreckage and place it into a plastic bag labelled 'bushfire'.

A concept image showing a half burnt flat Australian dollar paper note still on fire. It is a criminal offence to deliberately deface Australian money. (Getty Images/iStockphoto)

"We can help you if your banknotes have been partially or completely destroyed," the Reserve Bank writes on its website.

"The RBA will analyse the banknote debris you send us, determine the value and reimburse you the assessed amount for the money you have lost.

"If the cash was in a tin, drawer or wallet for example, it might be easier to include the receptacle and its contents in the bag."

Claims that involve sums of more than $1,000 will also require an identification reference form to be completed.

The Reserve Bank's guide to currency that is unfit to be in circulation. (RBA)

HOW BANKS ASSESS THE VALUE OF DAMAGED NOTES

The RBA takes great effort to keep only good quality notes in circulation, as torn, worn or broken notes degrade in-built security features in banknotes.

If a banknote is presented to the RBA as being "incomplete" – that is, it has pieces missing – then the full value of the note may not be paid to prevent people attempting to submit deliberately defaced notes for profit.

A bushfire is seen burning on Long Gully Road in the northern New South Wales town of Drake. (AAP)

The RBA therefore uses the following rules:

- If less than 20 per cent of a banknote is missing, then the full-face value of the note is paid.

- If between 20 and 80 per cent of a banknote is missing, then value is paid with the percentage of the banknote remaining. For example, if only half of $10 note is presented, only $5 will be paid.

- If more than 80 per cent of a banknote is missing, no value will be paid.

The RBA issues banks with specialised grids for each denomination of banknote, which helps bank staff work out the percentage of missing note.

One of the grids provided by the RBA to assess the percentage of missing banknote from a $5 note. (RBA)

Other reasons a banknote may be reimbursed if it has sustained significant or unusual damage.

Among the reasons for damage include heat damage (such as the bushfires), chemical damage, if the note has come into contact with blood, or if it has sustained damage that casts doubt on the note's authenticity.