On Friday night, about a thousand counter-protesters gathered at Belfast City Hall against a small anti-immigration demonstration.
A heavy police presence and barriers were in place to keep the two gatherings apart, with Donegall Square North closed to traffic.
The people at the anti-immigration protest were seen holding signs with slogans such as “Shankill Road says no to illegal immigration” and chanting “send them home”.
Trade union banners and signs with anti-racism messages were held aloft at the counter-protest, with chants of “when migrant lives are under attack, what do we do? Stand up fight back” and “Belfast is anti-fascist”.
Gerry Kelly and Caral Ni Chuilin, both Sinn Fein members in the Northern Ireland Assembly, were among the counter-protesters.
Police said there would be a “significant, visible” operation ahead of the protest and counter demonstration in Belfast city centre on Friday evening.
Queen’s University closed its campus and a number of businesses closed their offices as a precaution following violent scenes at an anti-immigration protest last Saturday.
There has been further disorder across Belfast during evenings since then, and 10 police officers injured.
Asst Chief Constable Melanie Jones said the police expected a very busy weekend across Northern Ireland with a risk of spontaneous protest as well as scheduled events such as the Apprentice Boys of Derry parade in Londonderry and the West Belfast Festival.
She also said that “officers may have additional powers to stop and search or require the removal of face coverings”.
“We will have a significant visible policing operation in place across Northern Ireland to ensure that everyone is kept safe,” she told media at a press conference at PSNI headquarters in east Belfast.
“We will be supporting the right to peaceful protest that is lawful, but this does not extend into intimidation, harassment or disorder.
“I encourage anyone who is planning to engage in protest to do so peacefully and within the law, and to engage with the police and follow our advice and instruction.”
Meanwhile in Crawley, West Sussex, hundreds of counter-protesters gathered outside a hotel and waved to the windows chanting “refugees are welcome here” as residents in the hotel, including a child, waved back.
Police guarded the hotel as police vans and two ice cream trucks surrounded the car park.
A sole opposing protester was seen outside the hotel earlier. Meanwhile counter-protesters sang “we stand together” and “hold strong, stop the deportations” in the sunshine on Friday evening.