FED-UP residents of Elms Drive and the roads surrounding Happy Mount Park have put boulders and makeshift barriers on grass verges to stop people parking there.
According to one resident, the problems are made worse when the weather is fine, as more people want to visit the park, but leave their vehicles on nearby residential streets.
The woman said: "You can't blame people for going to the park but they need to park with a bit more care.
"If an ambulance needed to get through, it would be impossible.
"It's shocking.
"Since the grass verges were damaged by the gas works, people have chosen to put boulders and wooden stakes as barriers to stop people parking there.
"A residents' parking permit would solve the problem.
"The visitors should use the car park in front of the golf club." A spokesperson for Lancaster City Council said: "Whilst we encourage people to visit Happy Mount Park and use the facilities it has to offer, we would also ask that if they choose to do so by private car, they park sensibly and within the law. There is a pay and display car park within five minutes' walk of the park which has parking provision for 106 cars and motorists can also park on certain parts of Coastal Road safely and for free.
"However, we are aware that there are problems around the area with people parking illegally and in ways which could cause an obstruction.
"Enforcement officers regularly patrol the area and we are working closely with our partners in an effort to resolve these problems."
Brian Abraham, assistant area manager at Lancashire County Council, said: "We have in the past helped to reduce unsafe parking close to Happy Mount Park by implementing 'no waiting' restrictions at the junction of Happy Mount Drive and Mount Avenue.
"The county council will continue to work with our colleagues at Lancaster City Council and Lancashire Constabulary to address any safety or obstruction issues that are brought to our attention."
