WASHINGTON  Faced with worsening forecasts for the economy, President-elect Barack Obama is expanding his economic recovery plan and will seek to create or save 3 million jobs in the next two years, up from a goal of 2.5 million jobs set just last month, several advisers to Mr. Obama said Saturday.

Even Mr. Obama’s more ambitious goal would not fully offset as many as 4 million jobs that some economists are projecting might be lost in the coming year, according to the information he received from advisers in the past week. That job loss would be double the total this year and could push the nation’s unemployment rate past 9 percent if nothing is done.

The new job target was set after a meeting last Tuesday in which Christina D. Romer, who is Mr. Obama’s choice to lead his Council of Economic Advisers, presented information about previous recessions to establish that the current downturn was likely to be “more severe than anything we’ve experienced in the past half-century,” according to an Obama official familiar with the meeting. Officials said they were working on a plan big enough to stimulate the economy but not so big to provoke major opposition in Congress.

Mr. Obama’s advisers have projected that the multifaceted economic plan would cost $675 billion to $775 billion. It would be the largest stimulus package in memory and would most likely grow as it made its way through Congress, although Mr. Obama has secured Democratic leaders’ agreement to ban spending on pork-barrel projects.