WASHINGTON — Lawmakers are under orders to finish action on President-elect Barack Obama's nearly $800 billion economic recovery plan by mid-February. But already it is plain that a set of serious fissures need to be bridged if the bill is to be completed within five weeks.

Obama urged Congress on Thursday to "act boldly and act now" to fix an economy growing perilously weaker, even as top Democrats said they dislike key provisions, especially the design of his tax cuts.

Democrats such as Budget Committee Chairman Kent Conrad complained openly that many of the incoming administration's proposed tax cuts wouldn't work. Republicans warned against excessive new spending, with both parties signaling the incoming president they intend to place their own stamp on the economic recovery effort.

Conrad, D-N.D., and Sen. Judd Gregg, R-N.H., also staked a firm position against using the economic recovery plan for permanent spending increases, opening a split with House Democrats hoping to use the plan to broaden eligibility for unemployment insurance and boost education spending.

"Doing things that would have a permanent effect when we face trillion-dollar deficits as far as the eye can see is just unwise," Conrad said.

A call for a $3,000 tax break for job creation drew particular criticism in a closed-door meeting, and numerous lawmakers said Obama had not ticketed enough of his tax proposal for energy.

But there was little or no dispute about the need for action, and Obama's remarks coincided with a pair of government reports showing fresh weakness in an economy already in recession. An updated reading on unemployment was expected to bring even more bad news on Friday.

"If nothing is done, this recession could linger for years," with unemployment reaching double digits, Obama said in a speech at George Mason University in Fairfax, Va. "A bad situation could become dramatically worse."

Obama's aides and congressional Democrats have been at work for weeks on legislation to create new jobs, help the unemployed, cut taxes and aid cash-strapped states. There also are subsidies to help the newly unemployed afford their health care, a big new effort to improve the energy efficiency of federal buildings, and tax credits for business investment in plants and equipment.

The details are closely held and subject to change — and the cost of various components seems to be bouncing around daily in the push and pull between the Obama transition team and congressional leaders.

Obama's chief political strategist, David Axelrod, and incoming chief of staff, Rahm Emanuel, heard plenty of ideas and criticisms during Capitol Hill meetings Thursday.