Walkers enjoying the scenic views at Cave Hill on Wednesday were shocked when they came across a leggy naked blond posing at one of the caves.
One rambler told the Belfast Telegraph that the blonde was doing "typical glamour modeling poses – nothing tasteful."
One eyewitness told the newspaper how he was sitting down enjoying a bar of chocolate at 2:30 pm when he first noticed the blond in the family friendly park.
“I was sitting drinking my juice and eating my Turkish Delight when what caught my eye was this girl with long blond hair and a bright pink tracksuit and pink shoulder bag," he said.
"I thought that looks really odd, it's not the way you would come up Cave Hill.
"There was a guy behind her, he had a grey bag with what looked like camera equipment.
"They went on up the path, he appeared to be getting his camera equipment out, then she took her gear off. She was posing on a rock and all sorts of poses, glamour sort of stuff.
"I couldn't see any detail from where I was but it was obvious it wasn't anything tasteful. She climbed up into the cave at one point, legs splayed out."
The witness said some walkers were so disgusted by what they saw that they turned back.
"I noticed at least three groups of people and a runner, they got half way to the cave, then looked up and walked down again.
"There was a teenager walking with a man and woman, they also turned and went the long way round," said a witness.
"Even when people were walking up towards them, they didn't seem in any sort of panic to stop and the girl made no attempt to get her kit back on. It was blatantly obvious what was going on."
Now Social Development Minister Nelson McCausland slammed what happened as "totally inappropriate and unacceptable behaviour."
"Cave Hill is a very popular location for walking and many families visit on a regular basis," he said.
"This is totally inappropriate and unacceptable behaviour for such a location and will have caused offence to many people who will have been in the area.
"I am sure it will be of concern to Belfast City Council and that they will want to make sure that this matter is fully investigated," he added.
A Belfast City Council spokesman said it "did not approve of that sort of behaviour in a public park," adding: "If anyone provides information on which to base an investigation we will investigate."