The Australian Prudential Regulation Authority may delay the introduction of tighter rules on liquidity until late 2010, the Financial Review reported. APRA is still to produce a final set of updated prudential rules on bank liquidity, following publication of a consultation paper in September.Industry unease centres on the practicality of the proposals, and mainly the one that will require banks to hold liquid assets equal to 30 days' requirements, to hold them mainly in government securities and also to require a bigger buffer against flighty "internet" deposits over some other categories of deposits.Banks (and perhaps smaller banks, in practice) will have to produce more detailed cash flow projections. Banks that struggled to report on liquidity to APRA during the crisis of late last year will also have to lift their game.