Amazon has launched a new program that gives it full price control over select third-party products sold on its marketplace, as the company's pricing policy comes under heavier scrutiny.

Amazon started inviting third-party sellers to a new program called Sold by Amazon (SBA) last week, describing it as a "new, hands off the wheel selling experience." Sellers who sign up to the program give Amazon permission to cut the price of their products at will, in exchange for a guaranteed payout called Minimum Gross Proceed (MGP), to ensure the discounts don't result in an unexpected loss for them.

"Sellers choose which products to enroll in SBA, and once enrolled, these products are priced by Amazon," the company wrote in an invitation to sellers seen by CNBC. "To ensure peace of mind, for each SBA product, Amazon will provide a Minimum Gross Proceed (MGP) amount to protect your margins."

Amazon's representative told CNBC the SBA program is designed to "save time and increase sales by automating prices so they can consistently and effortlessly offer customers great prices." It's also meant to provide sellers "peace of mind that they will never receive less than the agreed upon amount for that product."

The new program could blunt criticism of Amazon's pricing policy, which has drawn scrutiny for possible antitrust concerns.

In December, Sen. Richard Blumenthal, D-Conn., questioned Amazon's price parity clause, which blocks sellers from offering lower prices at other retailers, saying it could "stifle market competition and artificially inflate prices on consumer goods." Amazon removed that clause in March, but its policy still states that it could suspend products or stop giving access to the all-important "buy box" button if the seller engages in a pricing practice that "harms customer trust."

Earlier this week, Bloomberg reported that Amazon's current price policy implicitly forces some sellers to raise prices on non-Amazon sites because they don't want to get kicked off its marketplace, which now accounts for almost 40% of the U.S. e-commerce market.

But sellers with SBA-listed products can now lower their prices on rival sites without fearing that Amazon will boot them from the marketplace, while also protecting themselves from massive losses.

"Sellers are giving up full control over pricing, and Amazon is lessening their anti-competitive liabilities," said Blair Anderson, managing director of Anderson & Associates, a firm that helps merchants sell on Amazon.