The management of state-owned oil monopoly Petroleos Mexicanos said Friday it expected to announce its 2013-2015 collective bargaining agreement with its union next week.

"The labor negotiations are continuing. The idea is to complete them at the end of this month. We're talking about next week," Pemex's chief financial officer, Mario Beauregard, said in a conference call with investors.

Pemex has roughly 150,000 employees, as well as pension obligations with some 70,000 retirees that represent a major drain on the company's finances.

The company is looking to overhaul the current pension scheme to reduce a burden that last year amounted to 1.31 trillion pesos ($100 billion).

"Surely next week there will be an announcement with respect to the complete collective bargaining package for these two years. Right now, we don't yet have anything conclusive to report," Beauregard said in response to a question.

Pemex posted an accumulated net loss of 53.39 billion pesos ($4.12 billion) for the first half of 2013, compared to a positive bottom line for the same period of 2012.

In announcing its second-quarter and accumulated first-half results on Friday, Pemex noted that it posted net income of 6.82 billion pesos ($499 million) for the first six months of 2012.

In the first half of 2013, the oil company achieved average output of 2.53 million barrels per day, down 0.5 percent from the average production for the same period of last year.

The STPR oil workers' union is one of Mexico's most politically powerful labor organizations.

It is headed by Carlos Romero Deschamps, who also is a senator with the governing Institutional Revolutionary Party, or PRI. EFE