(Adds background, details on Slim)
MEXICO CITY, July 8 (Reuters) - Mexico's lower house of Congress on Tuesday gave general approval to legislation to reform the country's phone and TV markets and rein in telecoms tycoon Carlos Slim and broadcaster Televisa.
Lawmakers passed the general framework of the bill just as Slim's phone giant America Movil said it aimed to reduce its market share in telecoms in Mexico below 50 percent, delivering a boost to the government.
Opposition lawmakers made dozens of reservations on parts of the legislation that will be debated on the floor of the lower house. Final approval is likely to stretch into the night as lawmakers work through the reserved articles of the law.
The law is expected to pass without any major changes.
Mexico's Senate approved the legislation on Saturday and the bill will be sent to President Enrique Pena Nieto for publication once it is given final approval.
The bill fleshes out a constitutional reform that Pena Nieto pushed through Congress last year in a bid to increase competition in phone and television markets.
For years, critics have complained that America Movil and Televisa exert too much power over the daily lives of Mexicans.
America Movil dominates the fixed-line, phone and Internet markets, while Televisa is the top broadcaster and biggest player in pay TV.
The approval of the so-called "secondary laws" has been delayed by more than six months, complicating the work of a new regulator, the Federal Telecommunications Institute (IFT), that has already imposed tougher regulation on the two giants.
The approval of the telecoms law opens the door for Congress to pass separate secondary legislation on the government's most ambitious reform, the opening of Mexico's oil and gas industry to private investment after a 75-year state monopoly. (Reporting by Miguel Angel Gutierrez and Michael O'Boyle; Editing by Richard Chang)