By Denis Dumo

JUBA, Aug 9 (Reuters) - South Sudan plans to ask China for a $1.9 billion loan - a sum equal to more than a fifth of its national output - to be used for infrastructure projects such as roads and bridges, its foreign affairs minister said on Tuesday.

South Sudan's economy, which the World Bank values at $9.015 billion, has taken a hammering from a two-year civil war that ended in 2015, leading to a fall in oil production, its main source of revenue.

Oil has accounted in the past for most of government expenditure, while it has also taken loans from Chinese companies, offering to pay for them with future oil proceeds. Weak global oil prices have also badly hurt the economy.

Foreign Minister Deng Alor said the government was in talks with the Chinese government for the new loan.

"We (usually) present a list. Anything below $40 million, we ask the Chinese government for it to be a grant and anything above 50 million to be a concessional loan. So we are asking for $1.9 billion," Alor told news conference in the capital Juba.

"We want to focus and use this money, the loan that we are going to get from China, on infrastructure like roads, bridges."

Alor did not give more details on when the money was expected to be disbursed.

The two years of civil war that erupted after President Salva Kiir sacked Riek Machar as vice president in 2013 has killed more than 10,000 people and displaced more than two million, many of whom fled to neighbouring Uganda, Ethiopia, Kenya and Sudan.

Machar returned to the capital Juba in April after a shaky peace deal was signed last August but left again last month when new clashes broke out.

Kiir replaced Machar as vice president in late July with Taban Deng Gai, after Machar ignored Kiir's request to return to Juba.

(Writing by George Obulutsa; Editing by Gareth Jones) ((; +254 20 499 1232; Reuters Messaging: