WASHINGTON (Reuters)—U.S. Health Secretary Kathleen Sebelius ratcheted up the pressure on health insurance companies on Wednesday, urging them to forgo short-term profits to make coverage more affordable and to stop fighting the Obama administration's reform effort.

She told a health insurance industry group that costs and premiums would rise to unsustainable levels and more Americans and businesses would drop coverage if the Democratic-written overhaul of the $2.5 trillion health care system were killed.

"We will have a situation where the market is unsustainable," Ms. Sebelius said in a speech to a conference sponsored by America's Health Insurance Plans.

In their latest push to get a final health care reform bill through Congress, President Obama and his fellow Democrats have leveled sharp criticisms at the industry, saying it was putting profits ahead of patients.

Insurers could "give up some of their profits" to make premiums more affordable and work with Congress to enact the legislation, said Ms. Sebelius, who added that tens of billions of dollars had been spent on ads and lobbyists to kill the reform push in the past year.

AHIP President Karen Ignagni said the industry would accept Ms. Sebelius' challenge to offer more proposals for health care cost savings but said the bill did not go far enough in reining in soaring costs.

Insurers worried about exploding costs

"Our members are very concerned about insurance premiums," Ms. Ignagni said, adding the hikes were being driven by "exploding" costs.

"We are very disturbed about what is happening with underlying costs," she said as she introduced Ms. Sebelius.

Ms. Ignagni later told reporters the proposed legislation in Congress would make the system more expensive, not more affordable.

President Obama was set to address one aspect of the cost issue in a speech in St. Charles, Mo., later on Wednesday. The White House said he will back a bipartisan plan to stamp out waste in government-run medical programs for the elderly and needy.

The White House said the new effort to root out improper payments in Medicare and Medicaid could double taxpayer savings to at least $2 billion over the next three years.

"We cannot afford nor should we tolerate this waste of taxpayer dollars," the White House said.

An estimated $54 billion was lost through improper Medicare and Medicaid payments in 2009. Medicare is the government-run program covering elderly Americans and Medicaid is aimed at the poor.

President Obama and congressional Democratic leaders face an uphill battle to pass the roughly $1 trillion overhaul that would provide medical coverage to about 31 million Americans who lack health care insurance.

Ms. Ignagni said the legislation's requirement that people obtain health insurance coverage is not strong enough and would lead to higher premium costs.

Republicans have been united in opposing the bill and have criticized a budget process called "reconciliation" that Democrats plan to use to get a final bill to President Obama for his signature.

That process will allow the Democratic majority to pass final legislation by a simple 51-vote majority in the 100-member Senate instead of the 60 votes needed to overcome Republican opposition.