WASHINGTON — They were two early Christmas gifts for corporate America — with potentially far-reaching effects for investors and the financial landscape.

At the Justice Department and the Securities and Exchange Commission, separate actions this week both had the effect of easing landmark rules laid down in response to the 2002 crisis of corporate malfeasance.

Culminating an intense monthslong lobbying campaign by an array of companies, the five SEC commissioners voted Wednesday to propose a plan giving corporate managers more flexibility in assessing the strength of internal financial controls. It would especially benefit smaller companies.

A sweeping antifraud law known as Sarbanes-Oxley was enacted in 2002 amid the wave of scandals that engulfed Enron Corp., WorldCom Inc. and other big corporations. The law contains a key section requiring public companies to assess the strength of their internal safeguards to ensure that their financial statements are accurate. Companies have complained to the SEC that those rules are overly burdensome and costly, especially for smaller businesses.

The Justice Department, meanwhile, restricted its prosecutors' ability to crack down on companies that withhold confidential information during criminal fraud investigations, in new guidelines issued Tuesday that clipped back the aggressive legal tactics authorized after the scandals. They bar the government from seeking harsher penalties for companies that won't cooperate with prosecutors — either by denying the prosecutors corporate attorney-client communications or by helping their employees under investigation by covering their legal fees.

Deputy Attorney General Paul McNulty, who wrote the new guidelines, said they won't hinder prosecutors from vigorously pursuing companies accused of fraud and other white-collar crimes. But critics, including a group representing whistleblowers, called the changes a setback for shareholders and employees who risk losing billions if scandal-tainted corporations aren't fully prosecuted. They accused the Justice Department of caving in to pressure from business interests.

The actions by Justice and the SEC may eliminate the need for Congress to act in similar veins.