Around 3,000 people from all over the UK descended on the site in a disused opencast coal mine in Banwen, close to the Brecon Beacons, on Sunday.
Officers from South Wales Police, with the help of Dyfed-Powys Police and the British Transport Police, seized multiple sound systems and issued a dispersal order – but many refused to move on.
A police helicopter was also used to monitor the event.
Eight people have now been issued with a court summons, which could see them hit with a fine of up to £10,000 under the Welsh Government’s new coronavirus laws.
Others have been issued fixed penalty notices for parking offences, while some have had their cars towed.
Another vehicle being towed by Western RPU for parking offences at Banwen Rave. South Wales Police thank the public for their support while we manage this illegal gathering #positiveaction ^5051 pic.twitter.com/8iS9gxRlmK
— South Wales Police Roads Policing Unit (@SWP_Roads) August 31, 2020
The remaining ravers have been warned to either move on by nightfall on Monday or risk arrest.
Assistant chief constable David Thorne, of South Wales Police, told the PA news agency that the force had difficulty shifting people from the 4,000 acre site, which is usually used for rally car racing.
“When there’s 3,000 people to enforce a dispersal order on it becomes a massive issue,” he said.
“Even with the resources we were able to deploy at short notice it wasn’t sufficient to be able to move people on any quicker in a safe way.
“The fact we’ve got less people now with the officers we’ve got available we will be taking proactive and positive action if people don’t heed the dispersal notice.”
Locals have complained about rubbish being dumped and attendees defecating all over the site due to the lack of toilets and other facilities.
Mr Thorne said: “We think this is just completely irresponsible and disrespectful of the local communities.”
He added: “We believe those present to be from all over the UK – many of them have travelled hundreds of miles to get here so this hasn’t happened by accident.
“This has been planned and possibly planned for a little while, but unfortunately they have been able to plan this under the radar so none of the authorities were aware.”
Mr Thorne said those present had not been hostile to police, but added: “It’s people who have got their self-interest at heart and they intend on having a good time in their mind whatever that means – whether it’s drug use or alcohol use or just listening to music.
“The fact is that it’s illegal and it’s causing nuisance and disruption to local communities so we can’t allow that to happen.”
Multiple raves have been shutdown across the country this bank holiday weekend despite the threat of hefty fines.
We have rules in place to keep people safe.
You could face a fine if you decide to break them.
⬇️— UK Prime Minister (@10DowningStreet) August 30, 2020
Police in Norfolk were pelted with missiles when they broke up a 500-strong rave in Thetford Forest, while in London the Met Police said it had shut down 21 unlicensed music events.
Tomorrow we will police the same as we have today...by engaging with our communities and stopping any Unlicensed Music Events.#BankHolidayWeekend pic.twitter.com/FnC93OFoum
— Metropolitan Police (@metpoliceuk) August 30, 2020