A weakened crude oil market means investments might not materialize in time to finance Uganda's fledgling oil sector, the Bank of Uganda said.

The Bank of Uganda said in a monetary policy report for April there are lingering questions over the nation's oil development given the low price of oil and the investments needed to exploit the type of crude oil found in the country.

"Whereas oil production had been projected to start in 2018, this date could now be pushed out even further, given that the profitability of oil investments could remain depressed in the foreseeable future," the report said.

Crude oil prices are trading at around 40 percent below their June 2014 highs, forcing energy companies to spend less on exploration and production.

British exploration company Tullow Oil published a report in 2013 on its Ugandan developments. It said it has uncovered more than 1 billion barrels of oil in Uganda since operations began and most of that was in the country's Lake Albert basin.

Last year, the government unveiled plans to eventually build a new oil refinery that could produce as much as 60,000 barrels of oil per day.

The U.S. Energy Information Administration said Uganda holds an estimated 2.5 billion barrels of oil reserves. The Ugandan government estimates it could recover about half of that.

The Bank of Uganda said a failure to launch oil production by 2018 could impact the long-term prospects for the nation's economy.