Nigeria aims to be self-sufficient in both rice and wheat production within three years, a document by President Muhammadu Buhari's administration seen by Reuters showed on Saturday, a massive undertaking given current production levels.

The policy document was circulated among Buhari's ministers, whose portfolios are yet to be announced, on a two-day retreat. It also proposes overhauling the mining sector, including efforts to "ensure local and foreign investment" in the industry.

However, the five-page document did not provide details of how the administration led by the 72-year-old former military ruler would fund the planned changes in Africa's biggest economy, which has seen a slowdown in growth.

Buhari has previously stated long-term plans to encourage local manufacturing in Africa's largest oil producer, which has been hit by a fall in global crude prices.

"Self-sufficiency in rice production within 24 months" and "self-sufficiency in wheat production within 26 months" are goals in the agriculture section of the document, which also calls for "market guarantees for farm produce".

About 3 million tonnes of rice was produced in Nigeria last year, along with 64,000 tonnes of wheat, United States Department of Agriculture (USDA) figures show.

The West African nation is the world's second largest importer of rice and among the biggest buyers of U.S. wheat.

In 2012 it imported 2.3 million tonnes of rice - a record high, say U.N. statistics which also show some 4.1 million tonnes of wheat was brought into Nigeria in the same year - nearly double the amount imported in 2000.

The central bank has restricted access to foreign currency to import 41 categories of items, including rice, to stop a slide of the naira.

Nigeria stepped up import controls when Buhari led a military government in the 1980s.

The document also stated plans to "build a major north-south road within 36 months". Vice President Yemi Osinbajo has said a 25 billion naira ($126 million) infrastructure fund would be set up to improve the road, rail and power networks.

The creation of one million houses for the poorest of Nigeria's 170 million inhabitants within four years "using methods that create jobs" was also among policy goals outlined in the document seen by Reuters.