BOGOTA, March 13 (Reuters) - Colombia's main oil workers' union could start a threatened indefinite strike on March 19, its leader said on Friday, after previously saying the nationwide stoppage could begin any time after March 26.
Union leader Edwin Castano said members of the USO would join a 24-hour strike organized by the CUT umbrella union next Thursday and added that it may start its own indefinite action on that day.
Colombia's largest oil producer, state-run Ecopetrol says a contingency plan that will deploy staff to essential positions in the field will enable it to sustain regular output if the strike goes ahead.
Strike action by Ecopetrol employees is illegal because Colombian law prohibits stoppages in industries or job functions considered an essential public service. Many USO members work for third-party contractors hired by Ecopetrol.
Castano said he expected national oil production would be hit to some extent even if the stoppage is limited to next Thursday's event, which will start at 0600 (1100 GMT).
The USO is angered over thousands of layoffs across Colombia's million-barrel-per-day oil sector, and by Ecopetrol plans to shed some assets at a time when much lower oil prices are strangling cash flow.
"Workers are not accepting that this situation be blamed on the price scenario ... Oil policy has been badly handled in recent years. They have given tax breaks to companies. Today they are seeking to fire personnel," he said.
"We cannot be the ones who pay for the broken plates," Castano said.
International crude prices have halved since June last year. The London-traded Brent contract was hovering around $56 per barrel on Friday. (Reporting by Peter Murphy; Editing by Grant McCool)