Banks' debt rating downgraded

Ratings agency Moody's has downgraded the subordinated debt ratings for eight Australian banks as it says the government may not bail out all creditors in a financial crisis.

In a statement, Moody's Senior Vice President Patrick Winsbury said the downgrade reflected a global trend of selectively imposing losses on junior ranked creditors.

"We recognise that Australian bank supervisors have in the past acted in a manner to support all bank creditors," Mr Winsbury said.

But the global financial crisis showed "support can be provided selectively and bank recapitalisation costs shared with subordinated creditors", he said.

Moody's downgraded the subordinated debt ratings two levels for Australia and New Zealand Banking Group Ltd, Commonwealth Bank of Australia, National Australia Bank Ltd and Westpac Banking Corporation.