Advocacy groups for older people and the disabled urged lawmakers on Wednesday to let more people enroll in the Medicare drug plan this year without penalty.

More than 1 million Medicare beneficiaries would have to pay a penalty if they sign up for the drug program between Nov. 15 and Dec. 31. That fee is assessed because they failed to register during the first open enrollment period for the Part D benefit, which ended May 15.

The penalty is equal to 1 percent of the average monthly premium for each month of delay in enrolling. People who enroll later this year basically would have to add 7 percent to their monthly premium — or about $2.50 — as long as they participate in the program.

Lawmakers in both the House and Senate sponsored legislation to eliminate the penalty as soon as the spring deadline passed. The bills, however, have languished.

“Many beneficiaries were unaware or confused about whether or how to enroll in the Part D benefit and should not received a lifetime penalty as a result,” said the advocacy groups, including the National Council on Aging, Easter Seals and the Alzheimer’s Association.

The groups outlined their concerns in a letter to Senate Majority Leader Bill Frist of Tennessee and Sen. Harry Reid of Nevada, the top Democrat.

The Bush administration has dismissed the penalty for low-income people who qualify for extra help. But the administration says doing away with the penalty for the remaining pool of Medicare beneficiaries is a decision for Congress.

A bill in the Senate that does away with the penalty has 45 co-sponsors but has stalled because of objections.

A spokesman for Sen. Tom Coburn, R-Okla., who is one of the lawmakers holding up the bill, said the penalty was minimal and would not affect the poor.

“No program has done more to jeopardize Medicare itself than a bloated prescription drug benefit, which will give Donald Trump the same access to prescription drugs as any low-income senior,” spokesman John Hart said. “Removing this provision will only make a failing system worse.”

The penalty applies to those who were eligible for the program during the initial sign-up and did not enroll. The penalty would keep adding up with every month they do not enroll.

It does not apply to people who become newly eligible for the program.

Sen. Charles Grassley, R-Iowa, sponsored the legislation waiving the penalty because he said it would lead to greater enrollment.

“The bigger the pool, the more the risk is spread around, and the better the cost for everyone involved, from beneficiaries to taxpayers,” he said.