Senate Judiciary Committee Chairman Patrick Leahy has formally announced an April 17 hearing on comprehensive immigration reform legislation.

Department of Homeland Security Secretary Janet Napolitano will testify.

The hearing is in part the result of talks with the bipartisan Gang of Eight working on the soon-to-be unveiled legislation -- including Marco Rubio, who pushed for a slower committee process.

The mark-up is now not expected to begin until early May.

Some Republicans on the panel are unhappy with the schedule, saying it still does not allow enough time for the committee’s review of all the issues addressed in the bill.

Sen. Jeff Sessions of Alabama, a leading opponent of the reform effort, said in a statement that “to acquiesce to such a process would be to accept the Majority’s plan to rush through this massive legislation before the American people know what’s in it.” 

A day after a half-dozen Republican senators urged a slower and more public process for the crafting of immigration legislation, a key Democrat said that the timeline for completion of a bill will be delayed because closed-door negotiations have yet to produce a draft. 

In a statement, Senate Judiciary Committee Chairman Patrick Leahy lamented that his goal of completing a tentative version of a comprehensive reform bill by April won’t be met.

“Because we do not yet have legislative language to debate, the Senate Judiciary Committee will not be able to report a comprehensive immigration bill by the end of April, which was my goal,” Leahy said.

Leahy said that he has asked the White House to release its own version of reform legislation “for months” but that President Barack Obama has deferred to the bipartisan “Gang of Eight,” which is working on compromise legislation.

That group, Leahy wrote, has “engaged in secret, closed door discussions on their own proposal and … committed to completing it by the beginning of March.  That deadline and others have come and gone.”

The chairman’s statement comes a day after a group of Republican senators urged a slower process for the reform effort, writing to Leahy that the legislative language could present a “real problem” if it comes to the floor without being discussed in open committee hearings.

"If we are serious about protecting our national interest and the best interests of American workers, we must provide all members of the Senate, and, most importantly, the public, a full and fair opportunity to become adequately informed,” the group wrote.

At the end of this week, the Senate is scheduled to go on a two-week Easter recess. 

This story was originally published on Wed Mar 20, 2013 5:45 PM EDT