Wal-Mart's chief executive told America's governors on Sunday that he needs their help to make health care more affordable and accessible for the retail giant's 1.3 million U.S. employees because the company can't do it alone.

Lee Scott said Wal-Mart's health care costs have risen 19 percent in each of the last three years and that it's only a matter of time before it, along with other businesses, cannot sustain rising costs.

"We know our benefits at Wal-Mart stores are not perfect," Scott told the National Governors Association. "Do we want more of our associates' kids on our health plans? Of course we do."

Wal-Mart, based in Bentonville, Ark., has been the target of harsh criticism from watchdog groups and organized labor for what they say are costly and inaccessible plans. Under mounting criticism Wal-Mart last fall offered new lower-premium insurance aimed at getting more of its work force on company plans.

The company announced last week it is expanding that effort.

Scott said the "Value Plan" of $11 a month, now available in some areas, will be available to half of the company's employees within the next year. He also said children of part-time Wal-Mart employees will be eligible for health coverage as soon as the parent is and that the company plans to increase to about 50 the number of in-store health clinics that serve employees and the public.

He said improving the company's wellness program -- encouraging employees to eat right and take care of their bodies -- is its biggest challenge and the area where it has performed the poorest.

Scott also criticized bills filed in at least 22 states that would force the retailer to spend more on health care, saying they require companies to "spend an arbitrary percentage" of payroll on benefits.

"I believe what we're seeing is a little too much politics," Scott said. "I think we all know what the employer mandate bills are all about."

Democratic Gov. Tim Kaine of Virginia said he was "intrigued by (Scott's) discussion about the weaknesses of the employer-based health care model in this country and sort of wondered what his thought about the alternative would be."

Republican Gov. Mark Sanford of South Carolina said Scott was discussing the reality of soaring health care costs and said there's work to be done so somebody "comes up with the right way of skinning the cat and then serves as a best-practice model for a lot of other companies and states."