Nigerian President Goodluck Jonathan said on Thursday he had signed agreements worth around $10 billion over the next three years for investment in gas processing, petrochemicals and fertilizer plants.

Jonathan hopes his "gas revolution," launched two weeks before a presidential election, will indirectly create as many as 500,000 jobs, many of them in agriculture, and help improve power supply to homes and manufacturers.

"The investments agreed today will result in foreign direct investment of about $10 billion over the next three years," Jonathan told industry executives, government officials and diplomats at the launch of the plan in Abuja.

"The economic impact of this agenda will be endless in terms of employment and wealth creation," he said.

Italian oil and gas firm Agip and local energy firm Oando will build a central gas processing plant under the plans, Oil Minister Deziani Allison-Madueke said, while U.S. energy firm Chevron will supply the gas.

"We've agreed to begin with 175 million f³ of gas per day. We will deliver the gas once the pipelines and infrastructure are in place," Andrew Fawthrop, Chevron's managing director in Nigeria, told Reuters.

India's Nagarjuna Fertilizers said it had committed to building two fertilizer plants, an investment of around $2.5 billion, while Saudi Arabian firm Natpet, a subsidiary of petrochemicals firm Alujain, said it would invest $3.5 billion in a petrochemicals plant.

Africa's biggest energy producer has signed several memoranda of understanding with investors from China, Russia and the Middle East in recent years, many of them for projects which have yet to see the light of day.

Skeptics questioned the timing of the announcement and said turning the ambitious plans into reality would be key to realizing election campaign pledges of ending chronic power shortages and creating jobs in Africa's most populous nation.

Nigeria has the world's seventh largest gas reserves and is Africa's biggest crude oil exporter, but is hobbled by constant power outages and it is forced to import most of its domestic fuel needs because of the shambolic state of its refineries.

Successive governments have pledged to resolve the issue but have made little progress.