Three people were arrested as hundreds of pro-hunt protesters gathered outside a Labour party event attended by three Cabinet ministers.
South Wales Police confirmed that during the protest last night in Cardiff, three people were arrested for public order offences and three police officers were injured.
A spokesman said up to 250 people attended at the peak of the protest.
Chancellor of the Duchy of Lancaster Alan Milburn, Leader of the House Peter Hain and Northern Ireland Secretary Paul Murphy were all at the fundraising event in Cardiff.
The protest began peacefully at 5pm, but at around 8pm there were scuffles as some protesters apparently tried to gain entry to the venue.Part of Cardiff's busy Newport Road was closed off as police brought the situation under control.
Two of the arrests were made when a group of people apparently tried to push into the hotel lobby. The third was made when protesters were leaving the scene as a result of an alleged assault on a member of the public.
Mr Hain said he condemned attacks on the police.
Protester Adrian Simpson, of Carmarthen, said: "This is about sending a message to the Labour party. They have no idea. It is a ban based on bigotry and prejudice.
"This is the first salvo in a battle leading up to the election."
Mr Simpson said that although he worked for the Countryside Alliance, that organisation had not organised the "spontaneous" protest.
Another protester, Brian Hughes, a farrier, of Gilfach Goch, Rhondda, said: "The message is we don't want the Government to carry on with the ban. At the moment we are peacefully protesting, but we will go to any Labour party event. If need be, we will break the law."
At least one protester was injured as police horses were used to quell the demonstration. Protesters waved placards saying "Fight the ban, fight prejudice" in an attempt to distract the horses.
By 9pm, the protest had dispersed and a line of police in riot gear stood guard outside the entrance to the Holland House Hotel. Police also reopened Newport Road.
As he left, one of the protesters, David Thomas, a farmer from Llandrindod Wells, said there would be more protests in coming weeks.
He said: "Every time we know the Labour party is having a gala dinner or whatever we will be there protesting. Every time there are 10 MPs together, we will be there."
The police spokesman added that close communication had been maintained with the protest organisers to keep disruption to a minimum.
Chief Superintendent Bob Evans, South Wales Police Cardiff Division Commander, said: "We had been in contact with the protest organisers throughout the evening.
"We acknowledged their rights to protest and we did our best to keep the disruption to other members of the public to a minimum."
He said that missiles were thrown at one stage of the protest, and that previously unseen levels of aggression were shown to police officers.
Mr Evans said: "This has sadly introduced a new dynamic into the pro-hunt lobby in Wales, detracting from the actions of those seeking to peacefully demonstrate.
"Injuries have occurred as a result, that is extremely concerning and regrettable.
"We will continue to encourage co-operation from all community groups for any of their planned activities, and work with all members of the public to help them to enjoy their visit to Cardiff."