State officials say a Senate proposal to restore unemployment insurance benefits to more than 2 million long-term jobless would do more harm than good, warning that some states may ignore the legislation if it's passed into law.

The National Association of State Workforce Agencies, in a letter Wednesday to the Senate's party leaders -- Majority Leader Harry Reid, D-Nev., and Minority Leader Mitch McConnell, R-Ky. -- said the legislation would "substantially increase the administrative burden on states" by increasing costs and causing delays in the jobless receiving benefits.

"Some states have indicated they might decide such changes are not feasible in the short time available, and therefore would consider not signing the U.S. Department of Labor’s agreement to operate the program," wrote the group's president, Mark Henry.

The Senate on March 13 announced a bipartisan compromise to restart for five months the program for long-term unemployed workers whose jobless benefits went beyond state limits, which are about 26 weeks in most states. The program expired Dec. 28 after lawmakers failed to reach a deal.

The Senate is expected to pass the proposal, brokered by Sens. Jack Reed, D-R.I., and Dean Heller, R-Nev., after it returns Monday from a weeklong recess.

Henry said his organization doesn't have a position on whether to extend the benefits program because member states hold varying opinions on what to do. But he said that since most states are "struggling with antiquated and rigid computer systems," it would be "very hard to implement program changes quickly and effectively."

Henry also said the Senate plan isn't clear on how states would pay for administration costs. And a provision to backdate claims to Dec. 29 would be "nearly impossible" to implement in many states.

He added that the plan's "millionaire provision" — which would end unemployment insurance payments to anyone earning at least a $1 million annually — also would be difficult to administer.

House Speaker John Boehner, R-Ohio, said the state organization's concerns highlight the proposal's "serious problems."

"We have always said that we're willing to look at extending emergency unemployment benefits again -- if Washington Democrats can come up with a plan that is fiscally responsible and gets to the root of the problem by helping to create more private-sector jobs," Boehner said. "There is no evidence that the bill being rammed through the Senate by Leader Reid meets that test."

The cost of extending the program is about $25 billion for one year. But the proposal is fully paid for using a combination of offsets that include extending "pension-smoothing" provisions in the 2012 highway bill, which are set to expire this year, and extending customs user fees through 2024.