The lop-sided nature of credit supply from Australian banks emerges from the interim results of National Australia Bank, a supposed champion of business lending.The results show that A$14 billion of the $16 billion in growth in gross loans at NAB over the half year to March 2011 came from home loans, with virtually all that growth arising from the bank's Australian operations.Some of this uneven pattern of growth reflects subdued demand for business credit in most of the bank's geographic markets, a result of the flat economic outlook in Britain and New Zealand.Yet most of it reflects a strategic calculation to ramp up home lending in Australia for reasons that Cameron Clyne, the bank's chief executive, chose to spell out for investment analysts at a briefing yesterday.Clyne said that in 2009 NAB was growing mortgages at half times the system while growth in business credit for the bank was 1.3 times the system."We would not be able to participate in the rebound of business credit growth had we not actually grown mortgages aggressively because we would start to bump into all sorts of concentration numbers and other things, so we had to grow our mortgages.  "We want to get that side of the balance sheet moving."What's that actually done is give us substantial capacity in our various ratios now to participate in the business credit growth."