EBX group chairman Eike Batista made the pledge during a visit with Malaysian Prime Minister Najib Razak earlier in the day, the premier's office said in a statement.

"We are impressed with the potential that Malaysia has to offer and wish to announce our commitment of US$6 billion into Malaysia for high-impact strategic FDI investment to be implemented swiftly," Batista was quoted as saying.

EBX has interests in oil and gas, logistics and other fields.

Batista was ranked earlier this year by Forbes magazine as the world's seventh-richest man with a net worth of $30 billion.

Batista will work with Malaysian authorities "to expeditiously identify and implement" projects in the country, the statement said, without elaborating.

An aide to Najib also said he had no further details on the investments.

The statement added that Najib also spoke to Brazilian President Dilma Rousseff by phone late Wednesday and the two leaders pledged to increased economic and investment ties.

Rousseff invited Malaysia to work with EBX in the energy and natural resources sector in Brazil, offering it exploration and production operating rights, the statement said.

Malaysian national oil company Petronas will send a team to Brazil in September, it added, giving no further details.

Najib has solicited foreign investment as part of a plan to vault the country into developed-nation status by 2020.

Foreign direct investment in Malaysia rose 16 percent in 2011 to 364 billion ringgit ($117 billion), the government has said.

Critics of Najib's policies have pointed out that some previous investment plans announced amid fanfare eventually crumbled as foreign investors balked at Malaysian policies requiring preferential treatment for government-linked companies.

A report by Refsa, a think-tank headed by government critics, on Thursday criticised the government's approach in the developed-nation push as overly top-down planning, and "a delusion... that the government can drive the economy".