A draft memo to Wal-Mart's board was obtained from Wal-Mart Watch, a nonprofit group, allied with labor unions, that asserts that Wal-Mart's pay and benefits are too low. Tracy Sefl, a spokeswoman for Wal-Mart Watch, said someone mailed the document anonymously to her group last month. When asked about the memo, Wal-Mart officials made available the updated copy that actually went to the board.

Under fire because less than 45 percent of its workers receive company health insurance, Wal-Mart announced a new plan on Monday that seeks to increase participation by allowing some employees to pay just $11 a month in premiums. Some health experts praised the plan for making coverage more affordable, but others criticized it, noting that full-time Wal-Mart employees, who earn on average around $17,500 a year, could face out-of-pocket expenses of $2,500 a year or more.

Eager to burnish Wal-Mart's image as it faces opposition in trying to expand into New York, Chicago and Los Angeles, Wal-Mart's chief executive, H. Lee Scott Jr., also announced on Monday a sweeping plan to conserve energy. He also said that Wal-Mart supported raising the minimum wage to help Wal-Mart's customers.

The theme throughout the memo was how to slow the increase in benefit costs without giving more ammunition to critics who contend that Wal-Mart's wages and benefits are dragging down those of other American workers.

Ms. Chambers proposed that employees pay more for their spouses' health insurance. She called for cutting 401(k) contributions to 3 percent of wages from 4 percent and cutting company-paid life insurance policies to $12,000 from the current level, equal to an employee's annual earnings.

Life insurance, she said, was "a high-satisfaction, low-importance benefit, which suggests an opportunity to trim the offering without substantial impact on associate satisfaction." Wal-Mart refers to its employees as associates.

Acknowledging that Wal-Mart has image problems, Ms. Chambers wrote: "Wal-Mart's critics can easily exploit some aspects of our benefits offering to make their case; in other words, our critics are correct in some of their observations. Specifically, our coverage is expensive for low-income families, and Wal-Mart has a significant percentage of associates and their children on public assistance."