Those who are caught or reported to have discarded their cigarettes illegally may face a fine of up to $1,300.

Police said throwing lit cigarette butts from cars and trucks is dangerous any day as they can start bush and grass fires, and place lives at risk.

"It's also bad for the environment," A spokesperson from the NSW Police said.

"There are substantial penalties for people caught throwing lit cigarette butts from vehicles, especially during the bush fire danger period and days of a total fire ban.

"Penalty notices may be issued, and court action may be taken.

"The penalty for discarding a lit cigarette is $660. If it's a day of a total fire ban, the fine automatically is doubled to $1320."

A statement on the Fire and Rescue NSW website said they are called to hundreds of roadside fires each year believed to be caused by a discarded cigarette butt.

"It's no wonder we are called to so many fires on busy roads and freeways and by railway lines when they can start so easily," the statement said.

Police are encouraging witnesses to report any sightings of illegal cigarette discarding to http://www.rfs.nsw.gov.au/fire-information/cigarette-form.

Some of the information that will need to be provided includes location, date and time, vehicle registration plate details and description of the vehicle, as well ass your contact details as anonymous reports are not accepted.

Alternatively you can call 1800 679 737 and leave a message and an officer will make contact.