Walmart Inc. has asked a court to block a former top tax executive from joining Amazon.com Inc., saying the move would violate a non-compete agreement and "irreparably harm" Walmart's business by potentially tipping off its rival to strategic plans including potential merger targets.

Lisa Wadlin told Walmart (WMT) in January she was considering resigning as senior vice president, chief tax officer, but the company did not learn she was joining Amazon until separation papers were signed on May 15, according to the lawsuit.

Walmart, the world's largest retailer, said Wadlin's knowledge of its strategic plans "would be of immense benefit to Amazon," according to the lawsuit, which was filed late Wednesday in Delaware's Court of Chancery.

Walmart spokesman Randy Hargrove said many senior executives at Walmart agree to forego working for competitors with revenue in excess of $7 billion for two years after leaving the company.

"We believe Ms Wadlin's acceptance of a job with Amazon will violate her non-compete clause," Hargrove said.

Wadlin and Amazon did not immediately respond to requests seeking comment.

Walmart has been plowing money to into its online business to try to keep pace with Amazon (AMZN), which has muscled its way into the brick-and-mortar grocery business with its acquisition of Whole Foods.

Wadlin was hired by Seattle-based Amazon as a vice president of tax and tax policy, according to the lawsuit.

She brings with her non-public information including insight into Walmart's potential merger targets, according to the lawsuit. The Bentonville, Arkansas-based company said Amazon could use that information to thwart Walmart's deals, or force it to pay more.

Walmart is seeking a court order to enforce a non-compete agreement that the company said barred her from working for a competitor for two years after she departs Walmart, according to the lawsuit. It also wants the court to bar her from using or sharing confidential company information.