California budget officials could send more money to the Fresno Unified School District if state voters approve a package of tax increases in November.

But district officials warned Wednesday night that if the measure fails, it could mean Fresno Unified would have to slash up to three weeks from the school year.

Deputy Superintendent Ruth Quinto said the district is viewing Gov. Jerry Brown's proposed budget with "a great deal of caution."

In a worst-case scenario, districts throughout the state may need to cut school days in order to reduce expenses.

"Our kids can't afford that," said trustee Janet Ryan.

Ryan said she was concerned that if a cut in the school year was necessary that the district's employee unions might not go along.

"There will be no savings unless the [unions] agree," she said.

Brown's plan calls for a half-cent sales-tax hike and a boost in taxes on the wealthy. If voters approve the taxes in November, $4.4 billion in revenues would go to K-12 education and another $600 million would go to public universities and community colleges in the 2012-13 school year.

If the plan fails, $4.4 billion would be cut from K-12 budgets in 2013.

Budget problems over the last year have forced the district to dip into its $62 million reserve fund.

Last month, Fresno Unified used $20 million from its reserves to absorb state funding cuts after California tax revenues failed to meet projections. Fresno Unified's budget this year is $584.2 million.

The district also voted last month to use another $7 million to pay for additional teachers at 19 elementary schools and four high schools where classes have more than 39 students. The plan also will beef up teacher training in middle-school math and upgrade computer systems.

The grim budget news comes just a year after Fresno Unified went through a series of painful reductions.

At the end of the 2010-11 school year, the district slashed $33.8 million, which eliminated 684 jobs out of about 8,000 employees through retirements, attrition and layoffs.