California Governor Jerry Brown's revised budget with $6.6 billion more revenue may not avert a cash crisis looming in July that may force the most-populous U.S. state to pay bills with IOUs for the first time since 2009.

Brown yesterday proposed asking lawmakers to keep $9.1 billion of taxes and fees from expiring, then having a referendum to validate the extension in November or later, when a statewide ballot can be arranged.

The state won't be able to borrow cash from Wall Street in July or August with that validation vote pending unless Brown and lawmakers agree on spending cuts that would be activated if voters turn down the tax plan, Treasurer Bill Lockyer said.