The Albertbridge Road and Castlereagh Street were closed to traffic for a time, while motorists were advised by police to avoid the area.
A PSNI spokesman said the roads have reopened following the protest.
The area in east Belfast has seen some of the most violent clashes since the start of the flag dispute last month.
On Saturday night, a car was set on fire on Castlereagh Street, while police used water cannon to dispel rioting crowds.
The outbreaks of disorder followed the Belfast City Council decision to restrict the flying of the Union flag to 18 designated days.
Loyalist flag protests have also been held across Northern Ireland since the vote at the start of December.
In total 99 police officers have been injured and 110 people arrested in the last 40 days.
Local businesses have also claimed the disruption has cost them £15m.
Belfast Chamber of Trade and Commerce has called an urgent meeting with local retailers to discuss the downturn in trade over the Christmas period.
Chamber president Joe Jordan said: "There is no doubt that the past two months have been incredibly difficult for traders in Belfast.
"We want to hear the first-hand experience of businesses, along with their views and opinions on the current crisis."
The meeting will be held at the Europa Hotel in Belfast city centre on Wednesday.
Meanwhile First Minister Peter Robinson, deputy First Minister Martin McGuinness, NI Secretary of State Theresa Villiers and Tánaiste Eamon Gilmore will also meet next week to discuss the flag dispute.