The leaders want to avoid about $2 billion in welfare cuts the Democratic governor has proposed.
Senate President Pro Tem Darrell Steinberg, of Sacramento, said Monday that while it would be easier to just go along with Brown's proposal, lawmakers have a responsibility to their constituents, including the most vulnerable.
Brown's plan relies on voters approving an initiative in November that would temporarily raise sales taxes and income taxes on earners who make more than $250,000 a year.
Republicans oppose the taxes. But their votes are not required to approve the spending plan, which both houses are required to pass by Friday.