Maine’s superintendent of insurance is worried that a requirement in the new federal health reform law could cause further problems for Mainers struggling with high-cost individual insurance coverage.

Mila Kofman wrote a letter early this month to Kathleen Sebelius, secretary of the U.S. Department of Health and Human Services, asking for a waiver so Maine insurers won’t be required to meet higher medical spending requirements until 2014.

Kofman said she has been supportive of the reforms, but that the spending requirement may force one of the two private insurance companies that sell individual coverage to get out of that market.

“Loss of one of the two insurers would have a serious destabilizing effect in our individual market,” Kofman wote in the July 1 letter. The federal agency has not yet officially responded, according to a bureau spokeswoman.

The new federal law requires that insurers spend 80 percent of premiums on medical care for their patients. Maine has its own minimum medical spending requirement which “is somewhat but not substantially lower than the federal standard,” Kofman wrote.

Kofman asked for a waiver of the 80 percent requirement until 2014, when individuals who don’t have insurance through their employers will be able to buy coverage through exchanges that provide more competition.

About 40,000 Mainers are insured through the individual market and have been facing double-digit annual increases in premiums.