That unfamiliar incoming call to your cellphone soon might be from a debt collector.

Cellphones are largely off-limits to collection agencies, but proposals by the White House and Congress could change that.

Supporters say regulations have not kept up with technology and the fact that many consumers have replaced traditional landlines with cellphones. But consumer advocates warn that cellphone users could be bombarded with "nuisance" calls if debt collectors gain another avenue to reach — or hound — consumers.

"You give them any opportunity to call cellphones, they not only will do what is allowed but what is not allowed," says Lauren Saunders, managing attorney for the National Consumer Law Center. "This is one of the most abusive industries in the country."

Consumer advocates' concern is understandable; the Federal Trade Commission perennially receives more complaints about debt collectors than any other industry. But a change in the law would be a good occasion to update debt-collection laws to make sure cellphone users are not abused.

Right now, debt collectors and other businesses can call cellphones if they manually dial the number. But businesses typically use automated dialing systems to connect quickly with as many people as possible. (A business can use an auto-dialer to call cellphones if consumers give consent.)

President Barack Obama's deficit-reduction plan calls for a change in the law so people can be contacted on their cellphones if they are delinquent on government debt. This could include taxes, student loans and government-backed mortgages.

The president's plan says this would mean "substantial increases in collections."

A bipartisan bill introduced in the House last week is broader. The legislation would allow businesses to use auto dialers and recorded messages — sometimes called robocalls — to reach cellphone users.

Mark Schiffman, a spokesman for the debt collectors' trade association ACA International, says the latest restrictions on cellphones go back 20 years.

"The concern was not debt collectors," he says. "The concern was telemarketing."

The law prevented computer-generated calls to cellphones, he says, so consumers wouldn't pay steep phone charges to hear unwanted pitches.

But business groups say cellphone plans — and consumers — have changed.

Consumers now have flat-rate plans, they say, or pay a lot less for cellphone minutes.

And about 40 percent of consumers use a cellphone as their primary or only phone, says Howard Waltzman, a lawyer representing a coalition of business groups seeking to change the law.

That percentage is even higher among people in their 20s and 30s, he says: "You're talking about a generation of people who don't have a landline phone."

Waltzman says groups including the American Bankers Association and Air Transport Association want to update the law so companies can make informational calls to cellphones, alerting customers to fraud or canceled flights. You can get these informational messages on your cellphone now if you sign up, he says, but not everyone does.

He adds that the proposed change would still ban telemarketers from calling cellphones and that consumers still would be able to opt out of calls.

But consumer advocates fear a change in the law will open the door to intrusive calls to cellphones.

Because people switch cellphone numbers often, it's possible a consumer could be dogged by debt collectors pursuing the former owner of the number, says Paul Stephens, director of policy and advocacy with the Privacy Rights Clearinghouse.