Mobile payments may not be widely available for several years, but merchants, processors and card networks are already anticipating big changes in consumer spending patters — and their own business models.

A number of major retailers are overhauling their point of sale systems to accept contactless cards now, and mobile phones with embedded payment chips when they reach the market.

And though there is no consensus about when consumers will be able to initiate purchases with their phones, these early movers are putting pressure on smaller acquirers and independent sales organizations to equip their clients with the latest terminals as well.

Thomas A. Layman, a former chief economist at Visa Inc. and the founder and president of Global Vision Group in San Mateo Calif., said that recession-wracked consumers likely would warm to mobile payment technologies that could help them better manage their spending.

The economic upheaval this year has prompted widespread changes in spending, he said, as people shifted from credit to debit and curtailed their purchases.

"What we've experienced is the most serious change in consumer credit behavior that has ever happened," Layman said during a speech at the Strategic Leadership Forum Tuesday in New York, sponsored by the Electronic Transactions Association. Those trends may stick even after the economy recovers, and mobile payments could play an important role in consumers' altered habits.

He said credit card transaction growth will probably level off at about 5% a year, and debit card gains will "continue in double digits through 2012."

But various forms of alternative payments, especially mobile, could account for 20% of transactions by 2012, up from 2% now, he said.

Damien Balsan, the head of NFC business development for the Americas at the Finnish phone maker Nokia Corp., predicted that NFC-equipped handsets will begin arriving in the market in large numbers in 2010, enabling phones to be used for contactless transactions; millions of them will be in users' hands by 2011, he said.

"The first phase was cards. The second phase is the GoTags," he said, referring to stickers with contactless chips that can be affixed to users' phones, and which are available now. "The third phase is going to be the phones."

Mobile payments technology available would lead to major changes in the ways people spend money, Balsan said.

"There has to be a disruption in this market, some big movement a la PayPal," Balsan said during a panel discussion at the ETA conference. "With the mobile, everything is possible. We are going to see a PayPal-level disruption."

Bob Philbin, the president of TSYS Acquiring Solutions, a unit of Total System Services Inc., said one of those changes could even involve PayPal Inc.

Until now, the payments unit of eBay Inc. has confined itself to online transactions, in part because consumers cannot use laptop computers at the point of sale, Philbin said in an interview.

But smart phones, which make it possible for people to access the Internet while on the go, change that, he said. "As soon as PayPal figures out how to do brick-and-mortar, it's going to change the way Visa and MasterCard think."

However, he said it will be some time before mobile payments are common. "It could take three or seven or 12 years, depending on how fast the merchants go."

For now, it's the big merchants that are leading the way.

MasterCard has announced several agreements this year with major retailers that have upgraded their point of sale systems to accept contactless cards.

They include: 1,974 Home Depot Inc. stores; more than 870 company-operated outlets of the gasoline/convenience store retailer Hess Corp.; and 450 Sports Authority stores.

Diane Vogt-Faro, a senior vice president with Kohlberg Kravis Roberts & Co.'s First Data Corp. unit, said there is plenty of "cautiousness on the part of merchants" that have not yet adopted contactless terminals.

"It's a significant cost to move into contactless," Vogt-Faro acknowledged.

But financial companies should be investing in the technology, she said. "The banks are not moving into contactless, or just slowly. They need to move quickly."

Layman said that by embracing alternative payments, acquirers could set themselves apart from rivals that are moving more slowly.

"We think it will increasingly be driven by add-on services that differentiate you in the marketplace," he said.