It may not be the "welcome to America" that immigrants are expecting, but Uncle Sam's entry fees are about to go up nonetheless.

The federal government is nearly doubling and tripling the fees for citizenship and green cards respectively to raise more revenue to keep up with the influx of new citizens. Officials say they expect most foreign-born residents will be willing to pay it.

"Millions of people around the world would gladly pay many thousands of dollars for the opportunity to become a citizen," said Rep. Lamar Smith, R-Texas, ranking member on the House Judiciary Committee.

Thousands of dollars they will pay, particularly if families are applying together.

Under a proposal by the U.S. Bureau of Citizenship and Immigration Services, a green card or an adjustment to residency status would cost $905, up from the current $325. Green card holders, or permanent residents, who want to become citizens, would pay $595, up from $330.

USCIS Director Emilio T. Gonzalez, who testified before the House Judiciary Subcommittee on Immigration, Citizenship, Refugees, Border Security and International Law on Feb. 14, said the agency's daily operations are supposed to be paid with the revenues generated by application fees each year. Those revenues are falling short and are preventing the agency from modernizing and meeting efficiency goals.

Under the new fee schedule revenues would fund 99 percent of the agency's approximately $2.6 billion budget request for fiscal year 2008. The new revenues would help pay for to expand staff and upgrade facilities to cut the backlog of applicants 20 percent by 2009. The current fiscal year budget is $1.9 billion.

Gonzalez added that waivers would be available for refugees, those seeking asylum and other specific conditions. But as a fee increase, in general, he said it is not only warranted, but fair.

"The immigration benefits that USCIS confers are extremely valuable, and it is appropriate that prospective immigrants bear the full costs of the services provided. Law and policy have therefore long dictated that the costs of providing immigration benefits be borne by those applying for them," he testified.

But some members of Congress and a host of immigration groups say the hikes are unreasonable and hurt low-income immigrants the most. The increases could also deter non-Americans who are already legally here from becoming citizens, critics said.

"That kind of money is a bite out of anyone's budget," Rep. Zoe Lofgren, D-Calif., chairwoman of the Judiciary subcommittee panel, told FOXNews.com.

Lofgren also questioned why the bureau is pushing the burden onto immigrants when Congress has previously appropriated millions for the infrastructure and technology expansions the agency says it now needs to move into the 21st century.

"Is it reasonable to charge this generation of immigration applicants for a decade of neglect?" she asked, adding that the subcommittee has called for a full accounting of how past and current funding has been spent by USCIS.

"There are some who will struggle to pay (the fee increase). A lot of migrants have other expenses to survive," said Kevin Appleby, spokesman for the U.S. Conference of Catholic Bishops, which provides services for refugees and migrants.

The conference opposes the hikes, which Appleby noted, come at a time when the government is trying to discourage illegal immigration.

"This could be a barrier to engaging in the process. You could see an erosion of immigrants naturalizing and integrating into society," he said.

According to the most recent available federal immigration statistics, 1.2 million persons were issued green cards to become legal permanent residents in 2005. Also that year, 604,000 people were naturalized, becoming U.S. citizens for the first time.

Rep. Darrell Issa, R-Calif., said most immigrants were coming to this country to earn money at a pace and level unheard of in their home countries. As more people seek that future, the agency that processes their claims needs to adjust to provide enhanced security and anti-fraud measures in a post-Sept. 11 environment.

"The right to work in the United States is the right to make far more than 80 percent of the rest of the people in the world," said Issa, who supports the rate increase and believes it would be unfair to ask American taxpayers to subsidize the immigration process.

"The illegals are paying a lot more than this to get in," he said.

But not everyone who becomes a permanent resident in the United States works a high-paying job. Out of the 1.2 million who were granted permanent residency in 2005, 169,600 were classified as holding a white-collar job, 123,506 were in blue-collar positions, 206 were military and 828,000 had no occupation or an unknown occupation at the time of entry.

"Although they work here, they don't necessarily have the disposable income," Appleby argued. Since an immigrant can spend the rest of his or her life in the United States without having to become a citizen, they may just opt for that rather than incur the cost. The fee increase "may exclude a certain amount of immigrants from accessing the benefits of citizenship."

Issa said he isn't convinced. "I think all of us should realize that if you ask people who become citizens the vast majority will say, 'I wanted to be a citizen, the $595 wasn’t a big deal to me,'" he told FOXNews.com.

Others are looking at more fundamental problems than fee increases warrant. Mark Krikorian of the Center for Immigration Studies, which pursues immigration policy reforms that would set limits on legal immigration and improve the system's processes, said it is unreasonable to expect that user fees are going to fund the entire USCIS budget.

"The reason we are in this pickle is that Congress wants massive levels of immigration without (paying) for it," he said. "User fees can't keep the immigration agency up to date. It's one thing charging people to pay for the direct processing costs -- that I can go for -- but the problem is they have no money for infrastructure projects."

Congress has appropriated discretionary funds for special projects in recent years. This year the agency received $184 million in funds to pay for electronic identity verification systems for USCIS staff and private employers to screen immigrants. Nearly $50 million was also funded for modernization projects.

In 2006, the agency received $114 million for backlog reduction and modernization. This, combined with previous allocations, resulted in a reduction to the backlog of immigrant applicants from 3.8 million in 2004 to 10,000 in 2006, said Gonzalez. For 2008, however, USCIS has only requested $30 million for the employer verification system and hopes the rest will be paid for through the new fees.

USCIS spokesman Bill Wright said the last fee increase was in 1998 and it did not impact the flow of immigrants then. Since then, rates have not kept up with inflation. "We don’t anticipate that we will see a decrease in the applications."

The fee proposal is now subject to a 60-day public comment period, ending April 2, during which complaints and arguments in support of the measures will be taken into consideration, said Wright. A final ruling would come in June, the earliest.

"Will things be tweaked? Probably," he said. "We do want to establish dialogue, we do want to hear. Believe me, we've heard from the public."