The U.S. partial government shutdown have negative effects on both the U.S. and world economic growth, economists said here Tuesday, suggesting that Washington should do more to address its medium-term fiscal challenges.

The shutdown "will take a little out of fourth quarter GDP ( gross domestic product) growth (in the United States). That's lost forever on the level of GDP because those errors won't be made up, " said Vincent Reinhart, managing director and chief U.S. economist at Morgan Stanley, in a panel discussion held by the Council on Foreign Relations.

The U.S. economic growth will then reverses in the first quarter of 2014, but it will be difficult to discern growth six months from now, Reinhart added.

"We've been stuck in this 2-percent growth channel, and we've been expecting to be lifted up by capital spending to something higher," Reinhart said, noting that capital spending depends on business confidence, as well as on the confidence that households will spend.

"That is much more difficult to figure out," he added.

The federal government was forced into the first shutdown in 17 years on Oct. 1. The bitterly-divided Congress ultimately passed a legislation on Oct. 16 to lift the debt ceiling through Feb. 7, and fund the government through Jan. 15.

The temporary deal, however, failed to resolve the fundamental divide between Republicans and Democrats on spending and deficits.

Nemat Shafik, deputy managing director of International Monetary Fund, said "I think fiscal consolidation this year in the U.S. is going to take 2 percent off the growth," which is "a serious drag."

"And of course it hits most to the countries that are most closely linked to the U.S., (such as) Mexico, Canada, those sort of NAFTA (North American Free Trade Agreement) counties. But it does have global consequences as well," she added.

In Shafik's opinion, the way fiscal consolidations happening in the United States now couldn't be a worse way of doing it. "The sequester is a terrible way to do fiscal consolidation because it' s indiscriminate," she said.

Moreover, "the current policy is tightening in the short term and not dealing with the medium term. And the U.S. should be doing exactly the opposite, which is easing in the short term and dealing with the medium term fiscal challenges," Shafik said.

Talking about the next fiscal debates that will come again early next year, Lewis Alexander, managing director and U.S. chief economist at Nomura, said: "I think the next round is actually going to be focused on to what extent we can have some easing in the constraints in 2014 in exchange for long-run entitlement reforms."

Reinhart said politicians will kick the can down the road again because they worried about the next election.

He said it's hard to be optimistic about the U.S. fiscal prospects since "we just refuse to address the biggest asset overvaluation, which is the net present value of entitlements our citizens think they are going to get, because we don't have the fiscal system that can deliver."

However, Alexander cast a more optimistic view, saying the U.S. government has been through such situations before. "We had a government shutdown in the mid 90s, but we also had a surging growth that generated the largest post-war surplus we've had but for one year in 2000."

Alexander said "being on unsustainable fiscal path is actually not a political equilibrium in our system. That's what ultimately generated adjustment in the 90s, I think you are seeing that work through again, our political process is not pretty,... but it's generating consolidation."