Merseyside Police officers issued more than 60 people with fixed penalty notices for breaching Covid regulations following reports of an illegal rave in Formby in the early hours of Sunday morning (7 February).
At around 12.50am patrols attended Formby beach after groups of people and loud music were reported in the area.
Officers estimated around 100 people were present.
DJ equipment and lighting were seized and 64 people were issued with fixed penalty notices.
Two people were also arrested on suspicion of possession of Class A and B drugs.
The site was subsequently cleaned up by Sefton Council.
Deputy Chief Constable Serena Kennedy said: “Those who attended the event in Formby were astoundingly irresponsible.
“They were not only breaking the law but have put anyone that they come into contact with over the next few days, including their friends, family and colleagues, at risk of catching and spreading coronavirus with their utterly selfish behaviour.
“Targeted testing for the South African Covid variant is currently taking place across three wards in Southport after a second case of the new variant was detected. We have also seen cases of the E484K mutation of coronavirus in Liverpool this week.
“It is now as important as ever that our communities in Sefton and across Merseyside stick to the national lockdown rules which means people should not be leaving their homes for non-essential reasons or meeting up with other people outside their household or support bubble.
“It is only by following the rules that we will stop the spread of this deadly virus. If we all pull together, we will be able to return to normality a lot sooner.
“We need to do everything we can to protect the public during this pandemic and, rest assured, police will not hesitate to take action when people show such blatant disregard for the rules, as we saw in Formby.
“Anyone with information on who organised this event, who attended or any future planned similar events is asked to get in touch with us @MerpolCC or contact @CrimestoppersUK completely anonymously.”