The U.S. Health and Human Services chief says the Obama administration's proposed government health insurance plan would reduce costs by increasing competition.

Kathleen Sebelius said in an interview Sunday on U.S. television CNN's State of the Union the administration's plan would not replace private health insurance providers. She said it would strengthen the marketplace and give more options to people living in areas where private insurers have no competition.

In the United States, people purchase insurance to reduce the costs of health care services. But many insurance plans are prohibitively expensive. About 50 million people in the U.S. are uninsured.

President Barack Obama has proposed a government-supported health plan to expand coverage.

Mitt Romney, a former presidential candidate from the opposition Republican Party, said on ABC's This Week that Mr. Obama's proposal would be the start of a government takeover of the health care system.

Other members of the Republican Party say that government option would put private insurers out of business.

Some information for this report was provided by AP.