Demand for accommodation during the games will be high and many home-owners are expected to cash in by renting out spare rooms or vacant properties.
Some will be taking in paying guests for the first time.
The London Fire Brigade says anyone doing so needs to comply with Regulatory Reform (Fire Safety) Order 2005 which requires owners to carry out a fire risk assessment of their property, install smoke alarms and have a pre-planed escape route.
Deputy Commissioner of London Fire Brigade, Rita Dexter said: “We want everyone visiting London to have a safe and enjoyable Olympics and that includes not becoming a victim of fire.
“It is essential that those Londoners thinking of making a bit of extra cash by letting out a spare room during the Games are aware of their responsibilities under the law. If people ignore their responsibilities under fire laws, not only could they be prosecuted, they could be putting lives at risk.
“The message is simple, look around your home, make sure it is safe, ensure paying guests know how to get out in the event of a fire and install adequate smoke alarms.”