Ralph Norris, chief executive of Commonwealth Bank, told AAP the introduction of new liquidity rules by the prudential regulator will force the bank to hike interest rates by up to seven basis points."I think at this stage we'd be in the category of four to seven (basis points)," Norris said when asked for CBA's estimate on the additional costs required.In an interview with the news service Norris said: "We have to raise more funding and more liquid instruments."There's a limitation on the appetite in international wholesale markets for the amount of additional funding that we would have to acquire in order to meet those new liquidity requirements."