A man died at the gathering at Daisy Nook Country Park, due to a suspected drugs overdose.
Officers say those at the rave violated the current pandemic guidelines and incited others to break the rules, too.
At its peak, there were an estimated 4,000 people in attendance.
Mrs Rayner said: "I'm in touch with police, Tameside Council and Oldham Council about the illegal rave and the mammoth clean up required to get this beautiful area back to the state it should be in.
"It was devastating to see a place that's been a haven for so many people during lockdown covered in broken glass, cans and other debris.
"I am working with local police and ward councillors to see how we can improve the response should we be unlucky enough to find ourselves in a similar situation in the future.
"Those who attended the rave put themselves and their loved ones at risk.
"It was completely irresponsible of them and they should be thoroughly ashamed of themselves.
"They came and trashed the place, causing a lot of distress for nearby residents then left without a thought for those that would have to deal with the aftermath.
"Our NHS staff, police and key workers are selflessly putting themselves on the frontline, fighting coronavirus and keeping us all safe.
"Events like Saturday's rave increase the risk of spreading the virus and it's just not fair.
"The rate of infection in the North West is still of great concern and Tameside is a particular hotspot.
"We all have a responsibility to do our bit, observe the rules and protect the most vulnerable in our communities.
"I urge people to observe social distancing and follow the current Government advice on coronavirus."
Scores of furious locals have taken to social medía in a a blistering attack condemning the Daisy Nook rave, while Oldham Council leader Sean Fielding has praised the subsequent clean-up operation at the site.
