One victim, from Londonderry, told the BBC that blackmailers had demanded Â£10,000 not to reveal an intimate video on Facebook.
He described two months of "hell" after being tricked into making the recording by a woman he met online.
Det Ch Insp James Mullan praised the man for coming forward to warn others.
"We get about two or three reports a week across Northern Ireland of predominantly male people within the community who become victims of this type of incident," he said.
"I want to give people the confidence to come forward to the police and report it," he said.
"While we find it very difficult to get the people responsible, it's really important that, not just the police service, but other agencies are there to support these people."
Most of the scams originate in countries such as Philippines and Morocco, Mr Mullan added.
Christopher (not his real name) told the Mark Patterson Show how he received a friend request from a "very attractive young lady" on Facebook.
"Over a period of a few days we were chatting. She was a lot younger than I was. I'm in my 40s, she was, maybe, in her 20s.
"I was going through a bitter divorce at the time and you know... I was enjoying the attention, looking for a new relationship," he said.
"Over a period of time, it progressed to another level where she asked me did I want a video chat and the conversation became quite sexual.
"She got me on my phone through messenger and asked: 'Do you want to see me naked?'
"I put on video call, and all of a sudden I see a bedroom, and a girl naked, touching herself, caressing herself - she asked me to do the same thing.
"Then all of a sudden she left the camera and came back and she seemed to push some sort of a button, and all of a sudden it was a video of me doing what I shouldn't.
"She says: 'You've just broken the law, if you don't send Â£10,000 it (the video) will be posted to various friends.'"
One of the names that appeared on Christopher's device was the name of his daughter.
"I went into total panic, total panic and talk about cold sweats," he said.
The blackmailer managed to post the video onto Christopher's Facebook timeline, but he was able to swiftly remove it.
Christopher was given 24 hours to send his blackmailer the money.
During this time, he described how feelings of shame, disgust and most of all fear, nearly drove him over the edge.
In the end, Christopher reported the person to Facebook, and said the company was very supportive.
He also spoke to the Samaritans before confiding in two close friends, who accompanied him to the local police station.
"That constable was absolutely brilliant, she saw the stress I was under, she said 'you've broken no law'," he said.
He explained that the police wanted to trace the IP address of the computer being used by the blackmailer.
"The case is now closed, they never found out, but I went through hell for two months," he said.
Although still living under the threat of his video being released, Christopher said he felt good.
"If I could just use my pain and anxiety to help just one person, then to be honest, I feel quite proud that I've done something. That I took a stand you know," he said.
The police have been investigating 160 cases of internet sex blackmail in Northern Ireland over the past year, a senior PSNI officer has said.