MEXICO CITY—President Andrés Manuel López Obrador said the Mexican government wants to revise natural-gas pipeline contracts with private companies under which the state-owned electric utility is paying even when it hasn’t received fuel.

Mr. López Obrador on Monday lashed out at former government administrations and energy officials who he said have decimated the state power utility Comisión Federal de Electricidad, or CFE, through the privatization of the energy sector.

Mr....