Calderon's bill, would make it easier for Petroleos Mexicanos, or Pemex, to sign contracts with outside companies, and would let it offer them bonuses for oil finds and good performance.
 
It would also allow Pemex - which currently depends on US refineries to convert much of its crude into petrol - to hire specialised companies to build and operate new refineries for Mexico.
 
Falling output
 
Calderon says Pemex needs outside help to boost falling output in the world's fifth biggest producer.
 
"We do not accept the privatisation. We do not accept the reform sent
... by the illegitimate president"


Andres Manuel Lopez Obrador, defeated presidential candidate
Opponents say that he has exaggerated the crisis and manipulated figures because he wants to privatise the industry, which was nationalised in 1938.
 
The congressional television channel showed a chaotic scene, with clusters of politicians gathered around the podiums shouting at each other.
 
In the lower house, the protesters unfurled a banner saying "Closed".
 
The demonstration interrupted a debate on a routine measure allowing Calderon to travel to the United States for an April 21-22 summit of North American leaders in New Orleans.
 
Calderon lacks a majority in Congress and could face a tough battle with the opposition, some of whom accuse him of stealing the 2006 presidential election, to push the legislation through.
 
"We do not accept the privatisation. We do not accept the reform sent ... by the illegitimate president," Andres Manuel Lopez Obrador, the defeated presidential candidate, said on Tuesday.
 
Calderon wants Congress to approve his bill by the end of April before it goes into recess for several months.
 
Supporters of Lopez Obrador have taken over Mexico's congressional chambers a number of times since he was declared the loser to Calderon.