(Adds lawmaker comment and background)
MEXICO CITY, Aug 6 (Reuters) - Mexican lawmakers onWednesday gave final approval to an overhaul of the state-runenergy sector aimed at luring billions of dollars in newinvestments by foreign and private oil companies.
The senate approved a series of laws this week aimed atattracting companies such as Royal Dutch Shell Plc andExxon Mobil Corp, and help stem declining crudeproduction in Latin America's No. 2 economy.
President Enrique Pena Nieto said on Wednesday he would signthe set of bills into law next week, paving the way for privatecompanies to announce their plans to tap resources in theworld's 10th biggest oil producer.
The legislation fleshes out a constitutional overhaulapproved last year that ended the 75-year monopoly ofstate-owned oil company Pemex and opens up oil, gasand electricity markets to private companies.
Pena Nieto broke through gridlock in a divided Congress topass energy, telecommunications and banking legislation thataims to lift Mexico out of decades of sluggish growth in thecountry's most significant reform push since the NAFTA tradedeal with the United States and Canada in the 1990s.
Senators approved on Wednesday a final bill that amendspublic finance laws. The government finances around one-third ofits budget with oil revenues.
"Today concludes a period of valuable, profound andtransformative structural reforms that consolidate andstrengthen Mexico's foundations," said Senator Manuel Cavazosfrom Pena Nieto's Institutional Revolutionary Party (PRI).
The center-right National Action Party helped pass thelegislation that was opposed by leftist lawmakers who claimedforeign companies would siphon off Mexico's oil wealth forthemselves. President Lazaro Cardenas nationalized the oilindustry in 1938, making Pemex a source of national pride.
Officials expect the reforms will eventually spur enougheconomic growth to help curb the government's dependence ontaxing Pemex, which has seen output fall by more than a quarterfrom a peak in 2004 as heavy taxes cut into its ability toinvest.
The legislation gives the government flexibility on settingthe commercial terms for exploration and drilling contacts andprivate firms will be able to count reserves as their own, a keyprovision sought by publicly-traded companies.
Analysts project the reforms could spur tens of billions ofdollars per year in investments and companies could soon beginto announce plans to build pipelines and electricity plants, butestablishing oil and gas drilling projects may take years.
Mexican entrepreneurs could also rush in. Petrochemicalsmaker Alfa and billionaire Carlos Slim's conglomerateGrupo Carso could expand oil-related units.
Pemex asked to keep over 80 percent of its proven andprobable oil reserves and the Energy Ministry has untilmid-September to determine which fields the company will keep.
Once the ministry has made is decision, Pemex could movequickly to announce joint ventures with global oil majors but itis expected to take into the second half of next year before thegovernment auctions its first exploration and productioncontracts to private companies. (Reporting by Michael O'Boyle, David Alire Garcia and NoeTorres; Editing by Muralikumar Anantharaman)