Low morale, looming job losses and a failure to provide affordable healthcare meant workers may soon down tools at Coca-Cola and its bottling arm, Coca-Cola Enterprises (CCE), the Teamsters union said.
It held a special conference with investors, analysts and journalists on Monday to express its concerns about Coca-Cola, where the union represents 18,000 workers.
The conference comes in the same week Coca-Cola is due to hold its annual meeting.
A previous Teamsters strike across CCE bottling plants in 2005 caused disruption as drivers, packers and warehouse workers picketed lines.
Now, the union has warned of more "widespread work stoppages" in the near future.
"Coca-Cola's approach to labour relations has deteriorated, leaving workers with uncertainty and low morale," said David Laughton, secretary treasurer at Teamsters.
Laughton criticised Coke's attitude in the recent dispute over Powerade distribution in the US and also CCE's "ill-conceived, short-sighted restructuring plan", which is set to see 3,500 jobs cut over the next two years.
CCE announced the restructuring plan earlier this year at the same time as unveiling a $1.7bn loss for 2006, largely due to a $2.9bn impairment charge.
John Brock, the firm's chief executive officer, justified the restructuring plan: " Shifting consumer preferences away from carbonated soft drinks and onto non-carbs, the fact that our non-carb portfolio is less robust than it could be, and the impact of unprecedented cost increases on our 2007 profitability, have all combined to create the need for this change."
But workers were incensed after it emerged that top CCE executives were to receive discretionary cash awards for their performance during the year.
Brock himself got $1m, the firm said in a stock exchange filing after its results announcement.