NEW YORK (CNNMoney) -- California State University said Tuesday that it will raise tuition at its 23 campuses by another 12% this fall, thanks to a deeper-than-expected $650 million cut in state funding.

The hike is in addition to a 10% tuition increase that the university system approved last November for the upcoming school year.

Taking into account both tuition increases, full-time students will be paying an additional $516 per semester when they return in the fall. For a freshman, that amounts to an extra $4,128 over four years.

Tuition for full-time undergraduates enrolled in the public university will now run $5,472 a year, with fees averaging $950.

10 least affordable colleges

The tuition hikes come as California continues to struggle with its shrinking budget. The $2.1 billion in state funding the university will get in the upcoming school year will be the lowest level of support it's received since the 1998-1999 fiscal year. Making matters worse, CSU now enrolls 72,000 more students than it did in 1998.

"The enormous reduction to our state funding has left us with no other choice if we are to maintain quality and access to the CSU," said CSU Chancellor Charles Reed. "We will focus on serving our current students by offering as many classes and course sections as possible."

A third of the revenue from the tuition hike will go toward financial aid, the university said, adding that about 170,000 students will be fully covered by this aid or other grants and therefore won't need to worry about the tuition increase.

It's D-day for state budgets

To address the ongoing budget cuts at the school, the university has already slashed enrollment by about 10,000 students, reduced campus budgets by $281 million and cut the Chancellor's office funding by $10.8 million. The employee count has also been slashed by 4,125 -- or nearly 9%.

And this may not be the end of the university's financial woes. If state revenue forecasts aren't met by mid-year, CSU's funding would be cut by another $100 million -- amounting to a 27% drop from the previous year.

But some argue that the school has other ways of cutting back besides raising tuition. California Governor Edmund Brown wrote a letter to CSU on Tuesday, telling the school it shouldn't pay its administrators such hefty salaries if it's looking to cut corners.

Extreme tuition hikes ahead

"I fear your approach to compensation is setting a pattern for public service that we cannot afford," Brown said, adding that CSU has proposed to boost administrator salaries by more than $100,000. "At a time when the state is closing its courts, laying off public school teachers and shutting senior centers, it is not right to be raising the salaries of leaders who--of necessity--must demand sacrifice from everyone else."

Presidents in the CSU school system currently earn salaries ranging from $223,584 to $350,004, according to the California State Controller's salary database.