Oil-and-gas-rich Nigeria has signed a deal with two foreign firms, including a Bahrain-based firm, to explore its huge gas resources and shore up its foreign earnings, the gas minister was quoted as saying.

'We want gas resources to develop our resources, our economy and power. Since there is a lot of gas resources, we need the appropriate approach to explore our gas resources,' Olatunde Odusina said on Friday.

The memorandum of understanding was signed with an Indian consortium and Remington International Resources based in Bahrain.

Odusina said gas had the potential to replace oil as Nigeria's main foreign earnings if fully explored, stressing that the deal would enable the two companies to venture into the sector.

'As the world's seventh largest gas producer, Nigeria cannot, in all honesty, allow our gas resources to be left untapped,' he said.

'So there is the need for us to wake up to the challenges posed by the abundance of gas resources in our vicinity,' he added.

He said some $700 million was expected to be spent on the exploration in the north Delta region of the west African country.

Nigeria is the seventh world gas producer with about 187 trillion standard cubic feet (scf) of proven reserves, but flares off some 2.2 billion scf per day.