WASHINGTON (CNN) - Citing the failure of energy trader Enron Corp., Ralph Nader and other consumer activists called Saturday for fundamental corporate reform to curb what they see as abuses of power by large corporations.

"The creed of too many big business executives is greed, and it must be stopped," Nader said during an event called "Big Business Day."

Nader, the Green Party's presidential candidate in 1996 and 2000, called the event "the opening bell, the clarion call for fundamental corporate reform throughout our country."

"'Enronitis' has been a contagious disease, and it has not been good for the American people," he said.

The activists used a giant wood shredder to represent what they see as big business' consumption of American values. As speakers addressed the audience, people dressed to depict anonymous corporate representatives shredded pieces of wood with words such as "Truth," "Families" and "Democracy."

The activists called for a crackdown on actions by large corporations that they believe harm the interests of workers, investors, consumers, taxpayers and the environment. They also charged that government officials neglect the interests of their constituents by accepting corporate campaign money -- and that, as a result, they won't take action even when abuses and systematic flaws are uncovered.

Nader called the campaign finance reform bill, recently passed by Congress and signed by President Bush, "very, very modest." But he said it is a step in the right direction.

"At least it broke the myth that no campaign finance reform law could ever pass Congress," he said.

In the wake of the Enron collapse, which devastated the retirement accounts of many employees who had invested in the company stock, Bush has offered pension reform legislation. But Karen Friedman, director of policy strategies at the Pension Rights Center, dismissed his plan as "largely cosmetic."

"The president's bill really doesn't do very much. It doesn't do anything to address the issue of diversification of 401(k) plans, and it doesn't do anything to protect workers who lose money in these situations," she said.

Friedman said any workable retirement legislation should include diversification of 401(k) plans to prevent a total loss of assets.