People who spot ice cream vans operating during the coronavirus epidemic are being urged by a council to report them.
Leeds City Council said it has received reports of vendors still selling despite their licences being stopped.
A decision to fine vendors follows government guidance to only travel if necessary.
Deeming ice cream vans "non-essential" was "not easy", said the council.
Vendors who are caught selling are "operating illegally", warned the authority.
A Leeds City Council spokesperson said: "These are incredibly challenging times for us all and we need to work together as a city to make a difference and save lives.
"We know this isn't easy, but ice cream vans are not essential and this unnecessary contact is putting more people at risk."