Westpac deputy chief executive Phil Coffey says charging big banks for any funding benefit they enjoy from the Government would only accentuate "systemic risks".Smaller banks have called for some form of levy on major banks, arguing they benefit from the expectation they would get swift government support to ensure the payment of their liabilities - which in turn leads to explicit improvements in their credit ratings.The Customer Owned Banking Association last week launched a national advertising campaign questioning the cost to the community of these implicit Government guarantees.Coffey argued the campaign was "populist'' and misconstrued, and said any fee was likely to have unintended consequences."A fee would seem to make an implicit level of government support explicit. It seems very hard to argue that the fee is for nothing. It would clearly have to be documented in terms of what it was really for,'' Coffey said in a speech to the Committee for Economic Development of Australia in Sydney."It potentially creates a significant liability on the government balance sheet, and secondly and probably even more importantly, it explicitly distinguishes between the big, who have the government support, and the rest, who don't.''"Over time, this is likely to be reflected in relative funding advantages for the bigger banks, who would obviously be arguing that they are a safer place for all forms of deposited funding than those who don't have that explicit support. That can only exacerbate the systemic risk that people are concerned about in the first place.''Coffey said the credit ratings uplift they received did not mean the big banks were "guaranteed", as they still were still viewed as a higher risk than the government.