National Australia Bank's (NAB) chief executive, Mr John Stewart, has said that the bank's Irish and UK operations, which include National Irish Bank and Northern Bank, need "a lot of management attention".

Mr Stewart made the comment while rebuffing renewed speculation that the group was thinking of selling these banks after it delayed a planned presentation on its strategy for the UK and Ireland.

He restated the Australian bank's plan to integrate the four financial institutions and to identify a growth strategy and find ways to differentiate them in the crowded UK retail banking market.

Mr Stewart said NAB, which is struggling to recover from a damaging rogue-trading scandal, was pressing ahead with a three-pronged strategy for its four European banks: Clydesdale, Yorkshire, Belfast-based Northern, and National Irish Bank in Dublin.

Last week he offered assurances about the future of the Irish banks to the Irish Bank Officials Association.

Mr Stewart, who as chief executive of the Woolwich oversaw its transformation from a traditional building society into a cutting edge e-bank, said NAB was still experimenting with potential business models for the operations, including how best to target the affluent markets of the south of England where they have virtually no presence.

He said that he had not considered whether the four banks, once integrated, could be demerged and listed separately. Rather, they could provide an important element of diversity to NAB's earnings in the future.

At present, they provide nearly one-quarter of the group's total profits.

Mr Stewart, a former deputy chief executive of Barclays, was recruited last year to turn round and develop NAB's European operations.

He has unexpectedly found himself running Australia's biggest bank in the wake of its 360 million Australian dollar (€226 million) rogue-trading scandal. - (Additional reporting, Financial Times Service)