Washington ( CNN ) -- A sharp disagreement over the future treatment of undocumented workers on America 's farms is holding up progress on the comprehensive immigration reform bill being considered by the Senate 's so-called `` Gang of Eight . '' The two key sticking points are wages and the number of visas to be granted to undocumented farm workers , two sources close to the talks confirmed Friday . `` It 's the one major unresolved issue , '' one of the sources told CNN . The sources were unable to provide specifics in terms of the number of visas or wage levels under consideration . But , generally speaking , agricultural businesses have an interest in more visas and lower wages . Labor leaders , in contrast , typically support fewer visas and higher wages . Aside from the agricultural dispute , both sources stressed that the sheer complexity of the major reform bill could slow the timetable for its public unveiling . Senators are hoping to release the bill next week , but a significant amount of time is required for staffers from multiple offices to work their way through the lengthy proposal . The Democratic-controlled Senate and the GOP-controlled House each are working on immigration reform plans . Both chambers are expected to advance their respective blueprints some point soon after Congress returns next week from its spring break . The agricultural dispute is just one component of a plan that would provide the first major overhaul of America 's immigration laws since 1986 . Among other things , the Senate bill aims to provide a path to citizenship for an estimated 11 million undocumented residents . It would also create a new system for assessing the state of border security . Members of the Senate 's `` Gang of Eight '' are Sen. Lindsey Graham , R-South Carolina ; Sen. Marco Rubio , R-Florida ; Sen. John McCain , R-Arizona ; Sen. Jeff Flake , R-Arizona ; Sen. Robert Menendez , D-New Jersey ; Sen. Dick Durbin , D-Illinois ; Sen. Michael Bennet , D-Colorado , and Sen. Chuck Schumer , D-New York . A separate group of four senators -- Rubio , Bennet , Utah Republican Orrin Hatch and California Democrat Dianne Feinstein -- is trying to resolve the agricultural dispute .
Dispute over agricultural workers is slowing progress on immigration reform . Key sticking points for the Gang of Eight are wages and the number of visas for farm workers . Senate and the House are hoping to release immigration reform plans soon .