The Senate is set to take up a Democrat-backed measure that would delay increases for some federal flood insurance rates, though some Republicans are lining up behind an amendment that would gradually phase in the changes.

At issue are scheduled increases to premiums paid through the Federal Emergency Management Agency's National Flood Insurance Program, which is $24 billion in debt.

Sen. Robert Menendez's bill would delay some premium rate increases for four years until FEMA comes up with a plan to stabilize scheduled hikes called for in a bipartisan 2012 law. The New Jersey Democrat contends 5.5 million homes would see their rates skyrocket without changes.

The problems with federal program are largely structural. To encourage development near waterways, FEMA has long offered flood insurance rates at below-market value, which critics said understated the risk of building in such places and kept private insurers at bay. As a result, natural disasters such as Hurricane Katrina and Hurricane Sandy have caused the program's debt to balloon on the taxpayers' dime.

Republicans want some sort of rate increases to chip away at the debt the program has incurred, though many agree the forthcoming hikes are too drastic.

"I appreciate the people who passed the first bill. It was a big step in the right direction," Sen. Jeff Sessions, R-Ala., said Monday in the Capitol. "I think to some degree [the effect of the rate hike] was unanticipated."

Conservatives have offered initial support to a forthcoming amendment from Sen. Pat Toomey that would slowly boost rates over a number of years. The Pennsylvania Republican was tight-lipped about its details — including how he would pay for it so as not to increase the federal deficit, which some of his GOP colleagues noted was still an issue.

"The gist of it is to allow for a transition for the people who will be affected by changes in premiums. Allow them to have a more manageable transition, while at the same time maintaining budgetary integrity," he said Monday in the Capitol.

What, if anything, comes out of the upper chamber faces a tough path in the House. Speaker John Boehner, R-Ohio, told The Associated Press earlier this month that he won't pick up the Senate legislation, but that he might consider more modest changes.

The White House, for its part, appeared open to the legislation, though it stopped short of endorsement. It commented Monday that it "remains committed to working with the Congress to develop approaches that ensure economically distressed policyholders are not unduly burdened while maintaining the financial stability of the" program.

Menendez's bill would delay increases on two classes of homeowners — those who found out their homes are in an area more prone to flooding as a result of updated flood mapping called for in the 2012 law, and those who purchase a home currently covered under the federal plan.

But Menendez's bill would amount to "gutting" the 2012 flood insurance law by moving the rate increases outside the authorization period, said Nancy Israel, senior manager of the insurance program at business sustainability group Ceres.

"It won't do anything to protect the fact that they're living in harm's way. And we all pay. It's not just the homeowner. We pay for the subsidized rate and for the damage," she told the Washington Examiner.

And those damages are likely to become more acute as climate change pushes sea levels higher and makes storms more intense, said Robert Moore, senior policy analyst with the Natural Resources Defense Council's water program. While he said he was open to discussions about reducing the financial shock from increasing premiums, Moore said the Menendez bill would essentially amount to a repeal of the 2012 law.

But some Democrats hit back against that interpretation of the bill.

Sen. Chris Coons, D-Del., said he has heard concerns about "sudden, dramatic" rate increases from many in his coastal state. And he said critics' view that the bill would nullify changes to the flood insurance program is a "strained reading" of the Menendez measure.

"It is not my understanding that it will indefinitely avoid rationalizing the costs," Coons said.