Google is opening its online shopping service to merchants free of charge as it competes with Amazon in precious e-commerce and digital ads.

Merchants in the US will be able to use Google Shopping for free to proffer their wares by the end of April, and the goal is to do the same for sellers around the world before the end of the year, according to commerce unit president Bill Ready.

Google Shopping had previously showcased only retailers who paid to promote products to consumers searching online for items.

"As consumers increasingly shop online, they're searching not just for essentials but also things like toys, apparel, and home goods," Ready said in a blog post.

"While this presents an opportunity for struggling businesses to reconnect with consumers, many cannot afford to do so at scale."

The closing of physical shops due to the pandemic has accelerated Google's plan to make it free for merchants to sell with its online commerce service, according to Ready.

Beginning next week, results for searches in the Google Shopping tab will be mostly free listings. Google will display paid ads on results pages as well.

"For advertisers, this means paid campaigns can now be augmented with free listings," Ready said.

Online retail colossus Amazon uses a similar formula, mixing sponsored product posts with offerings by merchants and has been making an increasing amount of revenue from digital ads in the process.

Google said it is working with PayPal to allow merchants to use the financial transactions service for sales on the Shopping platform, making it easier for potential vendors to join.

Online shopping has surged, with Amazon center stage, as people sheltering at home to avoid coronavirus risk have relied on e-commerce for groceries, medicine, household staples and more.

"Solutions during this crisis will not be fast or easy, but we hope to provide a measure of relief for businesses and lay the groundwork for a healthier retail ecosystem in the future," Ready said.