A non-executive director of National Australia Bank (NAB) has hit back at attempts to unseat her by demanding mass board sackings over last year's currency option scandal that cost the bank A$360m (€220m) and 11 employees their jobs.

Catherine Walter is seeking the removal of the board, excluding John Stewart, the new chief executive, but including herself, in response to calls from seven non-executive directors that she resign. She came under fire from her colleagues for attacking a PricewaterhouseCoopers report into the fiasco, failing to co-operate with the investigation and for calling into question the integrity of her fellow directors. The NAB board has requested an extraordinary general meeting to put the issue to a shareholder vote.