Three fines were issued for breach of coronavirus legislation after a party was attended by around 50 people in Kirkby in the early hours of Sunday (11 October).
Reports were received just after 12.20am on Sunday from people concerned that a party was being held at the address on Simonswood Lane, Kirkby.
Officers attended and the occupants initially refused to open the door. Police were eventually granted access and around 50 people were seen in the house and back garden, where there was a marquee and loud music was being played.
A number of people made off over a rear fence, and some became aggressive towards officers in attendance.
Officers ordered all those not resident to leave and issued two people with fixed penalty notices for breach of coronavirus legislation. A 45-year-old woman was arrested to prevent a breach of the peace, as well as being issued with a fixed penalty notice.
Knowsley Chief Inspector Phil Mullally said: “We have known for some time now that the Liverpool City Region, which includes Knowsley, is in an extremely serious position relating to the spread of coronavirus.
“We have seen positive tests and hospital admissions rise sharply in recent weeks, and only yesterday it was announced the area is the only part of the country to be put on the "very high" Covid alert level from Wednesday.
“So many people across Merseyside have met the challenge posed by coronavirus with patience and great dignity, and continued to do what they can to manage the spread of the virus.
"This virus has impacted their birthday parties, weddings and funerals. But they are selflessly making huge sacrifices for the sake of the NHS as well as the health of themselves and others.
“But then there are people like those who organised this party in Kirkby who have simply not recognised the seriousness of the situation and have recklessly and thoughtlessly put people at risk, and flagrantly and noisily ignored Government guidance to only meet indoors with your own household, or bubble."
Chief Inspector Mullally added: “We will maintain our common sense approach in the difficult days and weeks we now face, our officers will encourage people they meet on patrol to respect the restrictions and explain why they are so important. When people flout the restrictions we will take action, as this incident shows.
“I want to appeal again to our communities to adhere to the guidance to keep your loved ones and ours safe. The safety of vulnerable people in Merseyside and our key healthcare workers depends on it, and the latest news from Westminster should leave everyone in no doubt about the consequences to people’s health and everyone’s freedoms if we do not all pull together and follow that guidance.”