More than 300 drivers have ignored parking restrictions imposed in Studland while a fire is ongoing, with some people reportedly even moving a fire hose so they can park.
Dorset Police has tweeted about the problem, saying firefighters "need the public to help them, not hinder them".
Around 90 firefighters were called to the heathland in Studland on Friday (12 August) after a large fire broke out.
Fire crews remain at the scene on Saturday and Dorset and Wiltshire Fire and Rescue urged the public to avoid the Ferry Road area and "stay off the heath".
However, Dorset Police said this message is being ignored.
The force tweeted on Saturday afternoon: "We have been called to reports that more than 300 cars have ignored the council’s no parking signs in Ferry Road, Studland.
"The restrictions are in place because the water hose is running along the road to allow firefighters to deal with the large heath fire there.
"We've even received reports that motorists have been moving the hose so they can park.Please return and move your vehicles.
"Do not park here: the fire service is working hard to tackle this blaze. They need the public to help them, not hinder them."