Mexico's senate has signed off on three of four bills to implement historic energy reform in the country, with the latest proposal covering structural changes to state oil company Pemex and the country's federal electricity commission (CFE).
Lawmakers passed the measure in an 87-27 vote Sunday after 12 hours of debate with more than 50 senators speaking.
Members of Enrique Pena Nieto's Institutional Revolutionary Party (PRI) sought to reassure the public that the measure, which includes about 80 legal changes does not privatise Pemex and aims to also protect its tens of thousands of workers.
"The new rules seek to modernise, update, strengthen and transform Pemex and the CFE into productive companies of the state, and of exclusive property of the federal government, so that they will be competitive in their respective markets," lawmakers said on a statement on the passage, which aims to give technical and managerial autonomy to both bodies.
The left-leaning Revolutionary Democratic Party reiterated its opposition to the changes, saying the new laws jeopardise social justice and "put at risk the labour stability of thousands of workers."
Constitutional reforms passed late last year and spearheaded by the Pena Nieto administration are poised to end Pemex's oil monopoly and open the country's oil sector to private participation for the first time in 75 years.
Lawmakers missed a late June deadline to complete secondary laws to implement the laws, but convened a summer special session and have been wrangling over details for weeks.
The bills have moved briskly however since being passed in committee early this week and presented to the senate starting Thursday.
The measures must also be approved by Mexico's lower house before heading to the desk of Pena Nieto.