– More than 50 tax breaks that expired as 2014 dawned, including a decades-old credit for research and product development by businesses, are not on a fast track for renewal because Congress needs to review them individually, a key member of the Senate Finance Committee says.

Utah Sen. Orrin Hatch, the committee's top Republican, said that, as part of examining the so-called tax extenders, the goal should be to let some go by the wayside rather than simply revive them all retroactively.

"I'm going to insist that we cut back rather than just keep all of them," Hatch said late last week. "We should do only the ones that we really should do."

Along with the business research and development tax credit, others among the 55 expired extenders allow older taxpayers a deduction for college tuition payments they make for their grandchildren, provide incentives for the renewable energy industry, and give a tax break for the building of racetracks.

Another lets filmmakers take a deduction of as much as $15 million if more than three-quarters of a movie's production occurred in the United States.

Hatch's comments were the latest indication that swift action isn't likely on the extenders.

House Ways and Means Committee Chairman Dave Camp, R-Mich., has said that his focus remains on promoting a comprehensive revision of the U.S. tax code. Scrutinizing the extenders would be part of that, with no separate action on them by the committee while Camp's push for the revision remains on the table.

Hatch didn't say which extenders he is inclined to keep or cut. He co-sponsored legislation last year with Sen. Max Baucus, D-Mont., chairman of the Finance Committee, to preserve the deduction for donating a property easement for conservation projects.

Some lawmakers want more urgency in addressing the renewal issue. Said Michigan Rep. Sander Levin, the ranking Democrat on the Ways and Means Committee: "We're going to have to talk about extenders fairly soon."

Some of the expired provisions have a higher priority for renewal than others, Levin said, mentioning tax preferences for research and experimentation expenses.

The research and development credit was first granted in 1981 and has been regularly extended.

Other lawmakers have urged Congress to reverse a cut in the deduction for mass transit commuting.

"Some of them are vital that we get busy on, so the sooner the better," Levin said.

Asked about Hatch's goal of reviewing the provisions closely before any extension, Levin said, "It's OK to review them, but it shouldn't delay our doing them."

Baucus said last week he is working with other Senate leaders on the expired tax provisions, while offering no timeline for their consideration.

He said lawmakers are "trying to see our way through" on how to deal with the tax extenders. "There's a lot of discussion, a lot of interest," he said.

Baucus praised Camp for keeping his push to revamp the tax code at the top of his agenda. Baucus last year joined Camp in spotlighting that effort, and he released discussion drafts outlining ways to change different elements of the code.

He has set the task aside as he awaits Senate confirmation to become U.S. ambassador to China after President Obama nominated him for that post in December. Baucus said the extenders issue remains the sole tax item on his agenda before he departs for his new job.