BOSTON — Massachusetts’ top insurance official said Monday that the state won’t allow consumers to keep health insurance policies that fall below the minimum requirements of the federal health care law.

State Insurance Commissioner Joseph Murphy said in a letter Monday to the Obama administration that substandard insurance policies are “virtually non-existent” in Massachusetts because of its first-in-the-nation health care law that took effect in 2007.

In a reversal of policy, Obama announced last week that millions of Americans would be allowed to renew individual coverage plans that otherwise would be canceled under the federal law in 2014.

Murphy wrote that unlike most states, Massachusetts has had a minimum benefit level for six years and that almost all health insurance policies are at or above the new national standard.

“To change course at this time, and delay certain market reforms, could cause confusion and significant market disruption,” Murphy wrote.

Murphy said in an interview that about 100,000 Massachusetts residents will need to change to what he called a slightly modified health insurance plan.

For example, some consumers might have to change to a lower deductible, he said.

He also wrote to Obama that the state is working to “seamlessly overlay the additional benefits” of the federal law over the state’s existing health care law.

He said the state has been granted a three-year transition to make sure that additional changes don’t disrupt the progress the state has made in expanding insurance.

Massachusetts’ 2006 health care law became the blueprint for the federal law signed by Obama in 2010.

Massachusetts has the highest percentage of insured residents of any state.