WASHINGTON - After months of negotiations, a bipartisan group of US senators aims to roll out a comprehensive immigration bill on Tuesday, giving President Barack Obama new hope that one of his top priorities for 2013 will advance in Congress.

While the timing could still change, several congressional sources said the eight senators - four Democrats and four Republicans - plan to introduce their bill on Tuesday.

That is the latest they can unveil a measure - one that would put 11 million people living illegally in the United States on a path to citizenship - if Senate Democrats are to stick with plans to hold a Judiciary Committee hearing on the bill on Wednesday.

Prospects for the legislation brightened in the Senate when a deal was struck behind closed doors on wages for foreign farm laborers working in the United States. Senator Dianne Feinstein added that the deal also would place a limit on visas for such workers.

"We have an agreement on wages and the visa cap," Feinstein said. The deal followed a six-hour negotiating session on Wednesday, she said.

The Democratic senator is not one of the so-called "gang of eight" writing the overall immigration legislation. But with her home state of California being an agriculture powerhouse, Feinstein was a lead negotiator on the farm worker provisions.

She refused to provide details of the wage and visa deal.

Between now and Tuesday, aides to the eight senators will work to finish drafting the bill that intends to further tighten security along the southwestern border with Mexico and pave the way for more foreign high-skilled scientists, mathematicians and engineers to work for high-tech firms in the United States.

Additional lower-skilled foreigners, from hotel maids to construction workers, also would be available to US companies hungry for cheap labor, but under tight controls negotiated by unions and business.

Agricultural employers complain that the current H-2A guest worker program sets wages too high compared to pay scales in rural areas and is unwieldy when growers need to recruit enough workers in a timely manner.

Wages can account for one-third of the cost of growing fruits and vegetables. The United Farmer Workers union has warned against unduly low wages that would make it hard for farm workers to support their families and could undercut wages in rural communities.

The farm worker portion of the bill was seen as the last major bit to be negotiated before senators could introduce their legislation.

Even at this late stage, negotiations were continuing on bits of the farm worker section of the bill and other miscellaneous matters, according to lawmakers and congressional aides.

But with Hispanic groups clamoring for action and Republicans in Congress still licking their wounds after being soundly rejected by Hispanic-American voters last November, the reform initiative was picking up steam, even though it still faced a difficult road ahead.

ENDING ILLEGAL IMMIGRATION?

Aware of the potential pitfalls, prominent advocates of immigration legislation were acknowledging the need to permanently fix border problems.

"I want to end illegal immigration ... so that we never have it again. I don't want another undocumented worker in this country," Democratic Representative Luis Gutierrez of Illinois told reporters on Wednesday after Hispanic lawmakers were briefed by Senate Democratic negotiators.

The government estimates that of the 1.1 million workers in agriculture, at least half are undocumented.

An immigration bill, which will attempt a comprehensive update of US policy for the first time since 1986, will try to end years of illegal hiring of foreign workers amid labor shortages in some sectors.

Craig Regelbrugge, a member of an agricultural employer coalition, said "there are still important issues unresolved" related to farm workers.

A key issue is the legal status for the tens of thousands of farm workers who entered the United States without documents.

The United Farm Workers union argues they should be given permanent resident status and the opportunity for citizenship. The Agriculture Workforce Coalition, representing employers, has suggested that legalization be tied to a commitment to work in agriculture for a specified number of months.

Farm labor reform has two major parts - a decision on how to treat workers in the country illegally and revamping of the guest worker program. Employers want a new program to replace the H-2A program, which they say makes it difficult to recruit enough workers in a timely manner and sets wages too high. The union has warned against formulas that would depress wages.

One proposal discussed by senators would allow up to 200,000 visas for new agricultural workers during the initial period of a new immigration law. That would be in addition to visas to cover the current number of H-2A workers, which has been 55,000-75,000 annually, according to an official familiar with the talks. After 2020, the Agriculture Department would set the cap on visas.

Wednesday's Senate Judiciary Committee will be an opportunity for Republican opponents of a comprehensive immigration bill to grill Homeland Security Secretary Janet Napolitano on how she intends to build on border security measures already taken. They also are expected to warn Democrats to not rush legislation.

Nevertheless, the panel is expected to move quickly after the hearing and schedule a session to consider amendments to the bill before sending it to the full Senate for a likely debate next month.

Republican Senator John McCain of Arizona, a leading member of the group of eight senators, told reporters that it was now "time to get it finished and introduced."

Another Republican senator in the group, Lindsey Graham of South Carolina, said he had "never felt more optimistic" about an immigration bill moving forward in the Senate.

But he said, "You always worry that something this complicated and emotional won't make it through."

Graham added, "The key is keeping business and labor (unions) together on the guest worker program" that aims to accommodate immigrant workers in agriculture and low-skilled jobs.