Wal-Mart is coping with a bad case of post-holiday indigestion.

After bingeing on Christmas inventory, the world’s biggest retailer has been forced to take drastic steps in recent weeks to clear stores and warehouses of excess goods, according to sources close to the company.

The culprit: disappointing December sales.

“It looks like they are in danger of heading into another negative ‘comp’ for the quarter,” according to an executive at a major Wal-Mart supplier, referring to the retailer’s fourth-quarter comparable-store sales, or sales at stores open at least a year — a key measure of performance.

Store executives are now scrambling to dispose of unsold merchandise across a slew of product categories, including food, cosmetics, clothing and toys, according to sources.

The situation has forced Wal-Mart in some instances to suspend the authority it normally gives to lower-tier executives who buy merchandise, according to an official at a second major supplier.

“The suppliers were told that the buyers would be the ‘CEOs’ of their categories, but their hands seem to be tied,” according to the executive.

The exec said a Wal-Mart buyer told him, “Sorry, I don’t have any more money [for inventory purchases] until next quarter.”

Returning unsold goods to suppliers isn’t usually feasible, so sources said Wal-Mart is hitting up vendors for cash to offset the cost of markdowns in a bid to shore up fourth-quarter profit.

Likewise, Wal-Mart is asking for discounts on spring and summer orders, and canceling or halting those orders until the older stuff is sold.

Wal-Mart officials declined to comment yesterday.

In November, Wal-Mart execs warned that declining comparable sales, which have dogged the big discounter for more than a year, may extend into the company’s crucial fiscal fourth quarter, which ended last week.

While Wal-Mart said its comparable sales might decline as much as 1 percent, it had also forecast a range for a possible increase of as much as 2 percent.

Optimism has since waned because “December was a dud for a lot of retailers,” said Stevan Buxbaum of The Buxbaum Group, a retail-consulting firm, noting that consumers had already shown signs of exhaustion before the late-December blizzard hit in the Northeast.

Wal-Mart appears to have bet more boldly in some key product categories than competitors, including Target.

“They scrambled to stock up on toys in November because they thought they were losing share,” said Gerrick Johnson, an analyst at BMO Capital Markets. “Then they ran into the problem of ‘where do we put this stuff?’ ”

Wal-Mart’s improvised solution was to display toys in odd parts of the store, including garden centers and auto parts — “a lot of random places where the customer wasn’t going to be looking for it,” Johnson said.

james.covert@nypost.com

