FAYETTEVILLE, Arkansas (Reuters) - Growing concern over the past actions of Wal-Mart Stores Inc (>> Wal-Mart Stores, Inc.) executives and board members threatens to cast a pall over the world's largest retailer's annual shareholder meeting and 50th anniversary party on Friday.

Large investors and a scrappy group of employee shareholders are calling for leaders such as Wal-Mart's chief executive and its chairman to be removed from the board of directors for their alleged connection to a bribery scandal in Mexico.

"Wal-Mart has given us an opportunity, with the Mexico bribery scandal, to pick up a head of steam," said Jackie Goebel, 60, a company employee for two decades.

Goebel belongs to a group called Organization United for Respect at Walmart, which is supported by groups including a major grocery union and has spent the last couple days encouraging stockholders to vote against several directors.

Wal-Mart has repeatedly said that it would not comment on the specific allegations until investigations are completed.

A New York Times investigation published in April said that management at Wal-Mart de Mexico (>> Wal-mart de Mexico S A B de C V), or Walmex, allegedly orchestrated bribes of $24 million to help it grow quickly and that Wal-Mart's top brass tried to cover it up.

The allegations are being investigated by the U.S. Department of Justice, the U.S. Securities and Exchange Commission and government agencies in Mexico. Wal-Mart is also conducting an internal probe.

Some shareholders believe that current board members, including Chairman Robson "Rob" Walton, CEO Mike Duke and former CEO Lee Scott, knew about the Mexico bribery and should have taken corrective action years ago.

Several large U.S. public pension funds, including the California Public Employees' Retirement System (CalPERS), already have signaled plans to vote against certain board members.

The vote is likely to be only symbolic since the family of Wal-Mart founder Sam Walton controls roughly half of the retailer's 3.4 billion shares.

But that has not daunted change-seeking shareholders.

"If at first you don't succeed, try, try again. We'll be back," said Carlton Smith, 51, who works in a Paramount, California store and owns Wal-Mart stock.

At Friday's meeting - which will feature singer-actor Justin Timberlake as host - Goebel also will introduce a shareholder proposal that calls on Wal-Mart to analyze and report the details of its executive compensation plan.

Wal-Mart's annual meetings are part business, part entertainment, and typically include surprise appearances and performances by celebrities.

Some 14,000 employees and shareholders are expected to attend what is normally a raucous event, complete with cheering sessions and musical acts, in a basketball stadium named for a relative of Wal-Mart founder Sam Walton. But this year's meeting looks likely to have its serious moments too.

(Editing by Andre Grenon and Michael Perry)

By Jessica Wohl and Lisa Baertlein

Stocks treated in this article : Wal-mart de Mexico S A B de C V, Wal-Mart Stores, Inc.