State-owned oil giant Petroleos Mexicanos, or Pemex, said it started the review process for its 2013-2015 collective bargaining agreement with its union, with the two sides forming a joint committee to go over the contract.

Creation of the committee marks "the formal start of negotiations on a new labor contract," whose review must be completed by Aug. 1, Pemex said in a statement.

President Enrique Peña Nieto's administration "has undertaken a vast reform program to transform Mexico and Pemex cannot remain excluded from these great changes," Pemex CEO Emilio Lozoya said.

The STPRM oil workers union has become a "factor for labor stability" in recent years, Lozoya said, adding that he was convinced that the union would continue to contribute to "the country's development."

"Oil workers are committed to the company," STPRM leader Carlos Romero Deschamps said in the statement released by Pemex.

The 2013-2015 collective bargaining agreement covers 150,000 unionized workers at Pemex.

The first collective bargaining agreement between the state-owned oil company and its workers was signed in 1942 and it has been revised 34 times.

Pemex had total revenues of $131.75 billion and assets of $161.8 billion in 2012.

Pemex, the world's No. 5 oil producer, accounts for about 40 percent of the Treasury's revenues. EFE