Police in Manchester were called to 494 house parties in just four days amidst social distancing.
Greater Manchester Police also dealt with 166 street parties, 122 groups playing sport and 173 park gathering, despite strict rules banning all three in a bid to stop the coronavirus outbreak.
Fireworks and bouncy castles were found at some of the get-togethers.
The lockdown breaches came ahead of the launch of a major operation to stamp out illegal raves over Easter to prevent the spread of Covid-19.
Thousands of people have turned up for secret raves in remote forestry in West Wales over recent years, but cops say it will "cost lives" if it happens this Easter weekend.
They fear officers will be put at risk if they are called to break up illegal raves by coming into close contact with the unwanted visitors.
The force has launched #OpFlamenco and officers will be stopping camper vans and vehicles registered outside the area in the unprecedented clampdown.
Superintendent Jon Cummins, head of Specialist Operations: "It is absolutely crucial that these types of gatherings do not take place.
"Illegal gatherings such as raves would be utterly irresponsible and without doubt put lives at risk."
Police are monitoring social media for information about raves being planned in Pembrokeshire, Carmarthenshire and Cardiganshire.
Supt Cummins said: "Action will be taken as soon as we gather any intelligence of an event being planned.
"However, these types of illegal events are carefully co-ordinated to avoid police attention, and organisers will always try to find new ways to avoid being found out.
"We will continue to respond swiftly to reports of illegal gatherings, and where appropriate will prosecute those responsible in order to protect our communities.
"We know raves can cause anxiety to the community they are held in, and if not dealt with swiftly are difficult to stop due to the sheer numbers of people involved."
Police will also be conducting "proactive patrols" of areas identified as possible sites for these types of gatherings.
Supt Cummins said: "We rely on the support of communities to report any suspicious activity immediately, so action can be taken to disrupt illegal gatherings swiftly.
"There has never been a more important time for us all to look out for each other, and report anything that seems suspicious - lives depend on it.
"It is very clear that the action each and every one of us takes today will have an impact on tomorrow, which is why everyone must stay at home."
Natural Resources Wales, which owns forestry which has been the scene of raves in the past, have put in "special measures" to prevent an invasion from people across the UK.
Phil Morgan, Land Management Team Leader, said: "During this time of Government lockdown, there really should be no one contemplating running or even attending an illegal rave.
"However, we are putting special measures in place over the extended Easter weekend to make sure all Natural Resources Wales sites are secure, making it as difficult as possible for anyone wanting to disobey the law.
"We strongly urge anyone who is concerned about suspicious activity in their local forest to report it to the police by calling 101, or 999 if it's an emergency."
Police have issued this anti-rave guide under #OpFlamenco.
Unusual numbers of vehicles, especially camper vans, vans or trucks, seen in the locality. Illegal trespassers may recce sites in advance of any rave.
People may approach landowners and ask around for land, in the guise of hiring it for acceptable activities such as gymkhanas or scout camps.
If you suspect anyone who approaches you for land hire might not be who they say they are, please do not hesitate to contact police.