An official at the Washington-based lender said on Monday.
Angola, which is sub-Saharan Africa's second-largest oil producer, has seen its economy grow rapidly since a 27-year civil war ended in 2002. But the country still needs to repair infrastructure and expand other sectors of the economy.
"We can make available $1 billion, fundamentally to finance infrastructure and agriculture," Gregor Binkert, the World Bank's country director for Angola and five other African countries, told reporters in Luanda.
"There is much need and the government has quite a coherent programme, so the World Bank will support it financially, through the International Bank for Reconstruction and Development," he said.
Binkert did not provide details on the financing. He did say that in coming months, the World Bank would define priorities, financing mechanisms and how to maximise the lender's resources.
The move could also be used to leverage more financing from the private sector, including pension funds and domestic and overseas banks that want to take part in Angola's infrastructure projects, Binkert said.
Oil output represents around 40 percent of Angola's gross domestic product and over 95 percent of export revenues.
Long-serving President Jose Eduardo dos Santos's government is trying to diversify the economy. That includes building up sectors like agriculture and fishing, which formed an estimated 10 percent of GDP last year.
The government is also spending billions of dollars to rebuild infrastructure destroyed by the war, including electricity, transport and communications networks.
The African Development Bank earlier this month approved a $1 billion loan for Angola to help develop its electricity network.