MEXICO CITY, March 21 (Reuters) - Mexico's state oil company Pemex said on Friday it had sent to the energy ministry a list of the oil and gas fields it wants to keep under a landmark energy overhaul, but declined to make the list public.
Under the energy reform passed in December, Pemex had until March 21 to turn in the list of fields it would like to maintain as part of the so-called Round Zero allocation.
The energy ministry has until mid-September to determine if Pemex has the technical and financial capacity to develop the fields it wants, but has yet to detail the specific criteria it will use.
Prior to the reform, Pemex was the only company legally permitted to produce hydrocarbons in Mexico, the world's tenth largest crude producer.
"Everything will be up to the energy ministry," a Pemex spokesperson said when asked if the list would be made public soon. "The ball is in their court."
An energy ministry press officer did not respond to calls or emails seeking comment.
"The fact that Pemex didn't reveal (the list) speaks badly about the practices of this government in terms of transparency and it's a very bad precedent for what comes next with the reform," said Miriam Grunstein, an energy specialist with Mexico City-based research institute CIDE.
In a statement, Pemex said it had submitted the list of fields along with development plans that include descriptions of projected investments, but did not provide specifics.
Pemex CEO Emilio Lozoya said last month the company would seek to keep the vast majority of its explored oil and gas fields via the Round Zero, in addition to all areas now in production without going into further detail.
But, he said Pemex would not seek to keep all of its deep water Gulf of Mexico acreage, where Mexico is believed to have nearly 30 billion barrels of potential oil equivalent.
The outcome of Round Zero will be crucial in determining the onshore and offshore acreage available to bid on by oil majors in international public tenders, expected by the summer of 2015. (Reporting by David Alire Garcia; Editing by Michael Perry)