After government testing showed that scores of consumer products carrying the Energy Star label did not deserve the listing, a wave of class-action lawsuits was filed against the companies that manufacture the products.

Now, at least one major manufacturer wants Congress to ban the lawsuits and is threatening to withdraw from Energy Star, an Environmental Protection Agency program, unless it gets its way. But consumer advocates say such lawsuits are a healthy form of enforcement.

A bill introduced by Representative Robert Latta, a Republican whose Ohio district is home to several Whirlpool factories, would prohibit class-action lawsuits if the E.P.A. came up with a remedy, like reimbursing consumers, for products that did not live up to their billing. The bill is co-sponsored by Representative Peter Welch, Democrat of Vermont, who is honorary co-chairman of a Washington group, the Alliance to Save Energy, which is also backing the change. LG Electronics is a founding member of the group, and Whirlpool is an associate member.

The proposed legislation drew immediate opposition from trial lawyers, who say the courts are often the only redress consumers have.