Leftist politician Cuauhtemoc Cardenas criticized the energy reform plan proposed by the conservative National Action Party, or PAN, and expressed support for the protests planned by the left against efforts to open Mexico's oil industry to private investment.

The PAN's plan is "badly laid out, badly supported," and "has exaggerated figures on the investment requirements" of the oil industry, Cardenas told Milenio Television.

The plan is incomplete because it does not link energy reform to fiscal reforms, the key to relieving state-owned oil giant Petroleos Mexicanos, or Pemex, of its high payments to the Treasury, Cardenas, the founder of the opposition Party of the Democratic Revolution, or PRD, said.

The current fiscal system practically "drowns the company," preventing it from investing to expand operations, Cardenas said.

The PRD wants to allow Pemex to have independence in setting its budget and managing operations, the leftist politician said.

Mexico's political leaders are expected to start looking at energy industry reforms in the next few weeks, with the focus on the future of Pemex and whether to allow private investment in the petroleum industry.

Pemex, which posted total revenues of $131.75 billion and had assets of $161.8 billion in 2012, is the world's No. 5 oil producer and accounts for about 40 percent of the Treasury's revenues. EFE