"We are going to reduce Pemex's spending or tax burden," said Lopez Obrador, adding a detailed plan will be put forward in September when the government submits its draft budget.
Mexico's successive governments have heavily relied on the Pemex revenues from its oil sales, which contribute up to 40 percent of the federal budget.
Feeding national budgets over years have consumed a lot of money to be otherwise used to strengthen the once major oil producer, according to the president.
Lopez Obrador has vowed to raise Mexico's growth rate to 4 percent from the current 2 percent by investing in productive projects, such as oil production and refining.
International credit rating agencies have threatened to lower Mexico's investment grade credit rating unless there is a substantial improvement in Pemex's weak finances.