Banks are likely to continue with little net debt issuance in the short to medium term, only selling enough wholesale debt to replace maturing liabilities, Reserve Bank assistant governor Guy Debelle said yesterday.    In a speech in Adelaide that surveyed trends in Australia's capital inflows, Debelle pointed to a probable pick-up in credit demand for banks."To the extent that investment in the non-resources sector is more likely to be intermediated by the banking sector than resources sector investment, the RBA's forecast pick-up in investment in the non-resources sector might see some pick-up in business credit from its current low rate of growth.""Even so, this would not require much of an increase in wholesale debt issuance given that deposit growth continues to outstrip lending growth by a few percentage points," Debelle said.He said the marked reduction of net offshore debt issuance by the Australian banking sector was "a trend which may be expected to continue for a while yet."