Middle-income adults living in the Golden State may see their health insurance premiums rise 30 percent next year because of the Patient Protection and Affordable Care Act, according to a government report.

Covered California, the state agency that will implement the law, said premium increases are most likely to hit those middle-income Californians who don’t receive health care coverage through their employers. On the other hand, lower-income consumers eligible for the law's tax subsidies could pay significantly less in monthly premiums compared to prior years.

The figures released last week came shortly after HHS Secretary Kathleen Sebelius conceded that health reform could cause some premiums to rise. Just how much reform will impact health care costs has been a major bone of contention between supporters and protesters of the law.