An online petition to keep Barry's Amusements open has reached more than 3,000 signatures, following the decision by the local council to refuse a preservation notice.
The Causeway Coast and Glens Borough Council planning committee voted not to issue a building preservation notice for the Portrush fun park during a planning meeting last week.
The decision has led to fears that the 1920s amusements complex could be knocked down and turned into flats.
Anouska Uprichard (36) from Craigavon started the petition on Friday after speaking to many friends who were worried about losing Barry's.
"I have seen so many people saying they would never go back to Portrush and that it would be a depressing place if Barry's is closed down," she said.
"I have been going to Barry's every summer since I was a little girl. I have two children of my own who I bring every year. For us, if Barry's is closed down it would end Portrush. Apart from the beach there is nothing else to do.
"Everything has closed down. Waterworld for example was closed down before. There is going to be nowhere left. People had told me to put together a petition online and I felt I just needed to do something.
"The reaction from most people is very positive. I'm not surprised it has got so many signatures so far. A lot of the comments are reflecting that we cannot let Barry's go. I'm hoping the petition might have an effect.
"I'd be very disappointed if they put apartments at the site. Especially as there is the chance they might just remain empty anyway as there won't be many reasons left to visit Portrush."
Councillor Philip Anderson sits on the council's planning committee. He explained that he would personally like the site to remain as a leisure facility.
"From an emotional point of view I wouldn't like to see it closed myself. For Portrush itself it is very important economically," he said.
"I support the message behind the petition. The more of the public who highlight the issue, the better it is. I don't think we can afford to lose Barry's. It is synonymous with Portrush as much as fish and chips is."
It is not clear yet whether Barry's will open as normal for the upcoming spring and summer season, with the future of the complex still very much up in the air.
SDLP MLA John Dallat described Barry's as a "honey pot for day trippers" over its long history and suggested that site being replaced by apartments would harm Portrush.
"The proliferation of apartments is killing off our seaside towns, with developers able to outbid those who would want to invest in leisure projects like Barry's," he said.
"Apartments do not create jobs or sustain the local community and are in danger of replacing the local indigenous population."