* Maresk-OGX blocks adjacent to existing areas
* Batista wants to raise stake in two blocks
* Potential of areas greater than expected
RIO DE JANEIRO, March 16 (Reuters) - OGX Petroleo said on Friday it plans to buy part of the 50 percent stake owned by Denmark's Maersk Oil in two Brazilian offshore oil blocks to expand its hold on a new oil frontier at the south end of the Campos Basin.
OGX already owns 50 percent of the two blocks and wants to increase the stake because the oil production potential of the areas is "huge" and greater than expected, Eike Batista, OGX's chief executive and controlling shareholder said.
Rio de Janeiro-based OGX is Brazil's No. 2 oil company by market value and expects to produce 1.4 million barrels a day of oil by 2020, more than half of Brazil's current output.
Batista's comments were made on a conference call with analysts on Friday. The call was scheduled to discuss plans by Batista controlled shipbuilder and ship leasing company OSX Brasil to raise $1 billion of new capital to finance its shipyard and naval construction projects.
OGX and Maersk each own 50 percent of the BM-C-37 and BM-C-38 blocks where Batista said OGX plans to raise its stake. Maersk is the operator. The blocks are adjacent to areas 100 percent owned by OGX and where the company began its first output in February.
The Campos Basin northeast of Rio de Janeiro is the source of about 80 percent of Brazil's 2.68 million barrels a day of oil and natural gas equivalent.
Maersk Oil press officials in Copenhagen were not immediately available for comment. Maersk Oil is part of Denmark's A.P. Moller - Maersk Group.
In January, Maersk produced about 2,037 barrels a day from its stake in the Polvo field in the Campos Basin. (Reporting by Jeb Blount; editing by Andre Grenon)