Mexico City - The growth potential for online shopping in Mexico, where consumers are more likely to scour shopping malls and street markets for goods, has put the country on the radar of the world's biggest retailers.

In June, Amazon.com Inc. began operating in Latin America's second-largest economy - where online retail sales, excluding travel and event tickets, are seen growing 30 percent to $5.7 billion this year, according to eMarketer.

While Web-based sales from Wal-Mart de Mexico SAB, El Puerto de Liverpool SAB and others represent less than 2% of all purchases, more than 15 million more Mexicans will gain Internet access by 2018, eMarketer said.

As the middle class grows and has more access to consumer loans, retailers are starting to test modified delivery options, circumventing payment obstacles that had prevented them from offering online shopping. Customers without credit cards now have options to pay in cash at delivery or even pick up packages at local convenience stores.

"I've never seen so much interest as now, not just from Amazon and consumers, but from other traditional retailers as well, to invest and come up with online offers," Juan Carlos Garcia, who heads Amazon Mexico, said in a phone interview. "There's an important demographical factor as more and more young people with digital mindsets are entering the economy," he added.

Millennials, people currently 15 to 34 years of age, are expected to swell the pool of digital buyers to 18 million next year from 14 million last year, according to Osbaldo Franco, a research analyst at eMarketer. Millennials already make up for more than half of Internet and smartphone users in Mexico, he said.