Chief Inspector Derek Riley said: "We attended Formby coastline alongside Sefton Council on Saturday and Sunday following reports large numbers of people had travelled there, some from as far afield as Manchester, Wigan and Birmingham.
"Since restrictions were lifted allowing people to spend more time outside, and the weather has been warmer, we have seen a rise in the number of people using local beaches, parks and beauty spots.
"But we continue to urge people to check ahead of travelling to popular destinations to ensure they can socially distance while there, that the destination is prepared for visitors and that facilities will be open and available and
"The advice remains that everyone should maintain social distancing at all times and that people should only meet up with the permitted number of people from other households when outdoors.
"Together with Sefton Council, who have restricted access to car parks and roads in popular areas, and Merseyside Fire and Rescue Service we are working hard to keep local residents and the wider public safe on what is a public coastline by patrolling key areas."
Chief Insp Riley added: "Parking issues, litter and minor incidents of disorder were reported to the council and police over the weekend, and a large quantity of alcohol handed into police by people making their way to Formby beach. A Public Spaces Protection Order has been in place since 2018 prohibiting the consumption of alcohol in areas including Formby, Crosby and Ainsdale beaches.
"More officers were deployed following social media posts about a gathering planned for late on Saturday night, and patrols attended the beach entrances on Lifeboat Road and Victoria Road to enforce the Public Spaces Protection Order and carry out stop searches.
"Throughout the night hundreds of young people and numerous vehicles were dispersed, 71 stop searches carried out and a large quantity of alcohol and nitrous oxide canisters seized. Fires were extinguished and three people were arrested on suspicion of possession of a controlled drug, one on suspicion of possession of an offensive weapon, two on suspicion of drink or drug driving and two knives were seized. A further 50 people were dispersed from Crosby beach.
"Our officers assisted Sefton Council with the clean-up of the litter on the beach the following day and will continue to patrol these areas on foot, horseback and on vehicles including quad bikes to ensure those attending are socially distancing and behaving sensibly, and taking action where necessary."