UPDATE 2-INTERVIEW-Mexico Senate sees April energy law proposal

(Adds fresh quotes, detail throughout)

By Catherine Bremer

MEXICO CITY, Jan 24 (Reuters) - Mexican senators expect to have a proposal ready in April for an energy reform aimed at revitalizing the sector and possibly bringing vital deepwater Gulf of Mexico oil within reach, a senior legislator said.

After a year consulting with Mexican and foreign experts, lawmakers from all parties agree the oil sector needs a shake-up to ensure Mexico's future as a world class oil exporter, Sen. Ruben Camarillo told Reuters in an interview Wednesday evening.

Camarillo, of the ruling National Action Party, or PAN, and secretary of the Senate Energy Committee, said his party hoped the law would let investment-starved state oil monopoly Pemex form alliances in areas like exploration and refining.

Even leftists opposed to private investment may agree to let foreign partners help Pemex drill in offshore oil fields sitting on the U.S. boundary, helping boost flagging output and reserves in the world's No. 9 oil exporter.

"I estimate it should be during April," Camarillo said, referring to when the senate committee would have a draft proposal ready to submit. Some lawmakers had seen a bill ready by end-February but most feel more time is needed.

"Pemex needs to be strengthened and made more competitive," Camarillo said. "This month and the next one we will most likely still be in the debating stage to try and put out a single initiative ... that all parties can sign."

The reform attempt will be conservative President Felipe Calderon's most ambitious yet since he took office a year ago and shook up Mexico's pension, fiscal and justice systems.