Last month, the finance ministry said the export of gold ore from Sudan would be banned once the refinery opened.

According to the Reuters news agency, Sudan hopes to sell gold worth up to $3bn (£617m) this year, double last year's gold revenue.

The country has great mining potential, but overall production figures are hard to verify because unofficial miners account for a large part of the gold industry, the agency says.

The new refinery, which will also process silver, is intended to reduce the amount of gold smuggled to other markets, such as Dubai, as producers should receive more money for higher-quality gold, it says.

"The refinery is the first project of its kind in Sudan and the second in Africa for producing and extracting gold and silver with high quality and purity," China's official Xinhua news agency quotes the director of the refinery, Mohamed Hassan Osman, as saying at the inauguration.

Another refinery director, Azhari Altayeb, said the plant would also process gold from countries in the region such as Egypt, Eritrea, Chad and the Central African Republic, reports the Sudanese Media Center, a website which has close links to the government.

South Africa's Rand Refinery, which describes itself as one of the world's largest gold refineries - processing "most of Africa's gold", has a capacity to produce 600 tonnes of gold annually.

South Sudan seceded in July 201,1 taking with it three-quarters of the former country's oil production - though it relied on pipelines routed through Sudan for export.

In January, a row with Sudan over oil transit oil prompted Juba to shut down its entire oil production of 350,000 barrels a day.

The move cut government income in Sudan, forcing Khartoum to impose spending cuts. Negotiations to end the dispute are ongoing.

Sudanese officials often state they hope gold will replace the lost oil revenues, according to the BBC.

However economists say some of the revenue disappears into the black market - and it still does not make up for all the oil money.

But in Sudan's difficult economic climate, it is one of the sectors providing some hope, our reporter says.