Officers attended the event in Acomb in York on Friday, after they happened across a gathering which appeared to be a breach of lockdown measures.
Some 10 adults were fined after it was discovered they were breaking rules which ban gatherings with people outside their household or support bubble.
North Yorkshire Police tweeted about the incident on the force's York City Neighbourhood Policing Team page, adding: "Please help the NHS frontline workers at York Teaching Hospitals NHS Trust by staying at home."
In a recent special report by The Yorkshire Post, staff at York Hospital's Covid-19 ward talked about the unrelenting stress they faced during the current crisis.
Tasmin Putt, a physiotherapist on the ward, said: “Holding the hand of someone as they die and you being a stranger and not a loved one, that’s very challenging.
“It definitely takes a huge emotional toll on us. It’s extremely upsetting watching people die on their own.”
The number of recorded coronavirus cases in York increased by 25 in the latest 24-hour period, official figures released on Friday show.
Public Health England figures show that 11,488 people had been confirmed as testing positive for Covid-19 by 9am on Thursday in the city, up from 11,463 the same time on Wednesday.
The health body is now including Pillar 2 tests – those carried out by commercial partners – alongside Pillar 1 tests, which are analysed in NHS or PHE laboratories and which made up the first stage of the Government's mass testing programme.
The rate of infection in York now stands at 5,454 cases per 100,000 people, lower than the England average of 6,225.
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