Consumers should not buy cheap fireworks at the last minute from unlicensed outlets or via social media, councils and emergency services have warned.
The Local Government Association (LGA) and fire authorities have warned that buying fireworks from car boot sales, vehicles or private houses could pose a risk to life and property.
The LGA is also encouraging people and businesses to store fireworks securely to avoid injury and damage.
The warning follows recent large-scale seizures of fireworks and incidents in which the explosives have been let off accidentally, severely damaging people's homes.
They include Tyne and Wear Fire and Rescue Service's seizure of almost 500kg of fireworks that had been stored in a garage alongside propane cylinders, petrol and live unsecured electrical wires, creating a risk of explosion, and £2,000 worth of fireworks found by Cambridgeshire and Peterborough Trading Standards which were being stored illegally in a van and sold through social media.
A kitchen was destroyed after a young child let off a firework in a home in Wrexham in an incident attended by North Wales Fire and Rescue Service.
Simon Blackburn, chairman of the LGA's Safer and Stronger Communities Board, said: "Fireworks are explosives and can be extremely dangerous, uncontrollable weapons when used inappropriately.
"These dangers are magnified when using illegal fireworks which are made from inferior materials that can cause life-changing injuries.
"People should only buy fireworks from reputable and licensed sellers, rather than from unlicensed outlets, such as car boot sales, or through social media."
Anyone who suspects someone is selling fireworks illegally should contact their local council's Trading Standards via Citizens Advice on 03454 040506.