Erik Thedeen, Sweden's central bank chair who became BCBS chair in May, told financiers gathered in Washington that the committee's work coordinating banking regulators globally is critical, and chided intense bank lobbying efforts to water down the stricter new "Basel III Endgame" capital rules.

Those standards overhauling how banks gauge their risk, in turn boosting the amount of capital they must put aside to absorb losses, has faced unprecedented industry pushback in the United States, as well as resistance in Britain and the European Union which have both delayed and watered down the rules.

They have argued the additional capital is unnecessary and will curb lending and hurt the economy.

But Thedeen said tougher standards would strengthen the global financial system and that governments should "lock in" those benefits as soon as possible. Relief that banks might enjoy from weaker rules could carry long-term costs for lenders and the economy, said Thedeen, who also poured scorn on banks' protests that the rules would hurt lending.

"As with other areas of economic policymaking, any perceived short-term gains are usually more than offset by longer-term pain," he told the Institute for International Finance conference, according to prepared remarks.

"Shaving off a few basis points of capital will not unlock a wave of new lending, but it will weaken your resilience."

U.S. banking regulators are deadlocked on how to proceed with their version of the Basel Endgame. Michael Barr, the Fed's top regulatory official, last month outlined an extensive overhaul of a 2023 proposal, roughly halving its capital impact, in response to industry criticism and litigation threats.

But with just over two weeks to go before the presidential election that could upend U.S. regulatory leadership, that effort has not advanced due to resistance from other key officials who believe the overhaul goes too far, or does not go far enough.

As several nations work to implement the Basel capital standards which they agreed to following the 2007-2009 financial crisis, Thedeen urged countries to stay consistent with one another and avoid a "free-for-all" of differing policies.

Global minimum standards make it easier for international banks to operate across multiple jurisdictions, and avoids a "race to the bottom," he argued.

"We may have different opinions about Basel III, but I think we can all agree that having a globally consistent level playing field is preferable to a patchwork of disparate regulations," he said.