Councillor Matthew Brown, leader of Preston City Council, said ice cream sellers trading during lockdown were 'irresponsible' and are putting lives at risk.
It follows reports of ice cream vans ambling along Preston's streets this week, with vendors spotted in Ashton, Cottam, Ingol, Larches and Penwortham.
"Ice cream is not an essential commodity", said Cllr Brown.
"It is irresponsible of ice cream traders to be encouraging people to come out of their homes at a time when everyone should be doing all they can to limit the spread of the virus, to protect vulnerable people, and reduce strain on the NHS."
He warned that "lives will be lost" if people continue to flout the lockdown.
"The message from the Government is people should stay at home except in specific circumstances – to buy food, or medicine, exercise once a day or to go to work where that work cannot be carried out from home.
"We must all adhere to this guidance or lives will be lost."
He also expressed concern for keyworkers in workplaces across the city that are failing to adhere to social distancing.
"I would also like to take the opportunity to emphasise the need for social distancing across Preston including in essential workplaces.
"A number of councillor’s have received reports from key workers saying they are not operating in environments with social distancing enforced when it could be.
"Members of the public should be doing all they can to help protect the NHS at this time."
The sight of the brightly coloured vans parking outside homes across the city has also angered parents.
Fulwood dad Lee Taylor was left fuming after one vendor parked up leisurely outside his home.
"The van was practically on my drive and my daughter was so upset when I told her she could not have an ice cream," said Lee.
"I had to try and explain why the risk to herself and our family is too great.
"She couldn't understand that if we had treated ourselves to an ice cream, we might have brought the contamination back into our house."