"We will go through a difficult time now because the government cannot afford to implement the budget they had adopted for the year," said Jose de Oliviera, an independent consultant in the oil sector.
"There is a risk of even bigger problems, like being unable to pay the salaries of civil servants, or a drop in the quality and quantity of basic social services, which will affect the poorest the most," said Elias Isaac, director of the Open Society Foundation in Angola.
About 54 percent of Angolans live on less than two dollars a day.
"Youth protest movements, which are viewed more and more favourably, are going to increase," said journalism professor and political analyst Celso Malavoloneke.
Demonstrations have been held with increasing frequency in Angola since 2011 and are quickly repressed by the police. The young people behind these gatherings are demanding the resignation of Dos Santos -- already in power for 35 years -- while denouncing poverty, inequality, a lack of access to water and electricity, and failures in the health and education systems.