Specially trained officers have now arrived at College Green to break up tonight's (March 23) protest.
Police vans and mounted horses have been spotted on Park Street as tensions between officers and campaigners build for the second time in two days.
Campaigners arrived in the city centre around 4pm to show their solidarity with travellers, who they claim are being unfairly targeted by the Government's planned Police and Crime Bill.
UPDATE: Follow live updates as riot police move in to disperse the crowds
Tents were set up, and at least 150 campaigners attended the event, which was hosted just two days after Bristol's riots.
A spokesman for Avon and Somerset police tweeted: "Specially trained public order officers are beginning to disperse a protest from College Green in Bristol.
"Officers had engaged with protesters and asked them to move on but tents and a sound system were set up.
"We remain in lockdown and we cannot allow this gathering to continue."
Reports from the scene suggest helicopters have been deployed and there are now police vans on Park Street.
The road has been closed, and bus diversions are in place.
One person tweeted: "On College Green right now, an entirely peaceful, camp out/protest is being evicted by about 24 police riot vans, about 12 cars, about five horses and helicopters."
