NATIONAL Australia Bank's leading finance executive, Mark Joiner, says the ability of Australian banks to grow their lending books will be constrained by tougher global rules and credit rating agencies taking a dim view on tapping global money markets for funds.

Speaking at a business lunch in Melbourne yesterday, Mr Joiner said the bank's wholesale funding costs would only peak in the middle of 2014, despite the Reserve Bank indicating funding costs - which have led the big four to resist passing on interest rate cuts in full - were showing signs of stabilising.

Mark Joiner says the ability of Australian banks to grow their lending books will be constrained by tougher global rules. Credit:JESSICA SHAPIRO

Mr Joiner, NAB's chief financial officer, said Australian banks had ''maxed out'' in terms of obtaining wholesale funding and those seeking to lend more would only do so to the extent they could also grow deposits.

''In my view, the Australian banks, for a long time, will only be able to buy the asset side of their balance sheet dollar for dollar with what they bring in on the customer side, this valuable retail side,'' he said.