WASHINGTON — Starting next year, the check will no longer be in the mail for millions of people who receive Social Security and other government benefits.

The federal government, which issues 73 million payments a month, is phasing out paper checks for all benefit programs, requiring people to get payments electronically, either through direct deposit or a debit card for those without a bank account.

The changes will affect people who get Social Security, veterans’ benefits, railroad pensions and federal disability payments. Tax refunds are exempt, but the Internal Revenue Service encourages taxpayers to get refunds electronically by processing those refunds faster than paper checks.

About 90 percent of people who receive federal benefits already get their payments electronically, the Treasury Department says. New beneficiaries were required to get payments electronically starting last year, and with a few exceptions, the rest will have to make the switch by March 2013.

“It’s just that natural progression of moving to how people are used to receiving their funds,” said Walt Henderson, director of the Treasury Department’s electronic funds transfer division.

Henderson said electronic payments are safer and more efficient than paper checks; in 2010, more than 540,000 federal benefit checks were reported lost or stolen. The switch will save the government about $120 million a year. Social Security will save $1 billion over the next decade, according to the Treasury Department.

“You think of that paper check floating out there in the delivery system, with personal information on it, it’s much more susceptible to fraud versus an electronic payment,” Henderson said.

Advocates for seniors say they understand the government’s desire to cut costs and take advantage of technologies that most workers already use. The food stamp program switched from paper coupons to debit cards in 2004.

But they have raised concerns about requiring the switch for older retirees who may not be used to electronic payments.

“This will affect some very frail elderly people who are living by themselves, many of them, and doing well, but usually within the context of that old paper check that they deposit in the bank,” said Web Phillips, a senior policy adviser for the National Committee to Protect Social Security and Medicare.

“The change has to be handled carefully and with a lot of sensitivity so that there aren’t people who lose track of a payment or don’t understand that they have a card that came in the mail that’s the source of their payment,” Phillips said. “That’s our concern.”

The switch is mandated by a Treasury rule issued in December 2010. Since then, the department has worked to educate the public. The government has created a website, www.GoDirect.org and a toll-free phone number, 1-800-333-1795, people can call for assistance.

“Treasury acknowledges they have a lot of education to do for people about how these things work,” said David Certner, legislative policy director for AARP. “We’re a bit concerned about how easy it’s going to be to provide education, particularly for some in this older population who are not familiar with debit cards and don’t have bank accounts.”

Certner said AARP wants the government to make it easier to get an exemption. Under the Treasury rule, current beneficiaries who are 90 and older won’t be required to make the switch. People can get a waiver if using a debit card would impose a hardship, but the Treasury Department says those would be “extreme, rare circumstances.”

These waivers are not well publicized on the government’s website.

“There are several million people who receive paper checks today,” Certner said. “Some of them do it because they have worked out arrangements for them that work.”

AARP also has concerns about fees associated with the debit cards. The Direct Express cards are issued by Comerica Bank, Treasury’s financial agent. Each month, benefit payments are added to the cards, which can be used to make purchases or withdraw cash from ATMs.

There are no fees for using the debit card to make purchases. They can be used at any retailer that accepts MasterCard debit cards. If a card is lost or stolen, the beneficiary is protected from unauthorized use as long as the missing card is reported promptly.

Cardholders can make one free ATM withdrawal each time a payment is registered in the card. Subsequent withdrawals will cost 90 cents each, and all withdrawals may be subject to fees by the owner of the ATM.