US Democratic Senator John Kerry said Wednesday night that the health care system in the United States had gotten worse under President George W. Bush over the course of the last four years.

"It's not working for the American family...Five million Americans have lost their health insurance in this country," Kerry said in his third and final presidential debate with Bush in Tempe,Arizona.

The 90-minute debate, which started at 9 p.m. EST (0100 GMT), is the only one devoted to domestic issues such as jobs, health care and social security.

"Children across our country don't have health care. We're the richest country on the face of the planet, the only industrialized nation in the world not to do it," Kerry said.

"I have a plan to cover all Americans. We're going to make it affordable and accessible," he said.

Bush retorted that the Kerry plan was only an empty promise. "I want to remind people listening tonight that a plan is not a litany of complaints, and a plan is not to lay out programs that you can't pay for," he said.

"If every family in America signed up, like the senator suggested, it would cost us 5 trillion dollars over 10 years. It's an empty promise. It's called bait and switch." Bush said.