(Adds comment on appeals process, context on production and global supply disruptions)
LIMA, March 14 (Reuters) - A strike at Peru's top copper mine, Cerro Verde, may end next week if the labor ministry declares it illegal, the head of the union said on Tuesday after negotiations with owner Freeport-McMoRan Inc ended without an agreement on labor demands.
Workers began the strike on Friday to demand better family health benefits and a bigger share of the mine's profits, but the ministry has issued a preliminary decision against the stoppage that the union is appealing, Cerro Verde Union President Zenon Mujica said on a phone call.
The appeals process will likely take about a week and workers will have to go back to work if the ministry hands down a final ruling against the strike, said Mujica.
Freeport-McMoRan did not immediately respond to requests for comment.
Production at the mine, which churned out nearly 500,000 tonnes of copper last year, has fallen by 50 percent since some 1,300 of about 1,650 workers joined the strike, Mujica said.
News of a possible return to normal operations at Cerro Verde could ease pressure on global copper prices as supply has been disrupted by a labor stoppage at BHP Billiton's Escondida mine in Chile and a dispute over export rights at Freeport's Grasberg mine in Indonesia.
Mujica said Cerro Verde workers will vote this week on whether to call for regionwide protests.
Reporting by Mitra Taj and Marco Aquino; Editing by Richard Chang