So why does a good Christian man feel drawn to what he calls these “dark, ugly places”? As a father of three daughters, the northern Thailand-based activist is passionate about rescuing girls from the sex trade.

“About 12 months ago I went with my wife and family on holiday to a project that was being launched. During the day we did all the family and touristy stuff then at night-time my girls went to bed and I went out with the boys to rescue people,” he says.

Over that week, Kirwan and his team rescued 22 girls aged between 12 and 15 years old. When the girls from that project wrote their stories, it emerged that eight out of ten had been gang-raped and their violent abuse had been videoed or photographed.

One girl from a rural village had been duped into working in the city brothel by being promised work in a restaurant with a friend.

“This kid was worried and afraid but still had a glimmer of hope that her friend was going to turn up, so she did what the lady said and she went to the lounge and sat there for a long time. A lot of men were looking at her and asking her for sex but she didn’t understand what that meant,” Kirwan says.

“Eventually a guy came over and said ‘If you’re living here that means I can have sex with you,’ so he literally grabbed her and dragged her into the room. This kid was screaming and asked him to stop but obviously he didn’t and he raped her.

“Prior to that she was a virgin and from that time onwards she was an emotional mess and she would just cry all the time. She said that many times she was taken into that room and was violently raped and beaten by multiple men at the same time. She said each time this happened she would scream at the top of her lungs for anybody to come and rescue her and nobody came.”

“Now she’s got hope and she’s got a future.”

For four months this 15-year-old been forced to sleep with up to 10 men a night and the brothel owner-manager, the mamasan, kept everything the men paid, ensuring that she was always in debt (for rent, food, clothes and makeup).

“The first time she saw us in the brothel she wondered why we were looking at her and smiling at her and we called her over and were just asking friendly questions. She was confused because she said nobody had ever been interested in her like that. ‘All they ever wanted was to have sex with me.’

“When we left that night we gave her a tip and we said: ‘we think you are special, we think you are a good girl. And her response was ‘are you sure? I don’t think so.’ She was really quite confused because she hadn’t experienced good guys coming into the brothel because good guys don’t go into brothels.

“We went back the next night and … she was quite scared because she saw us talking to the mamasan (the owner) and so she assumed that we were going to try and take her away and abuse her, because obviously that’s happened to her many times before. But we sat her down and we showed her some photos of some children we had already rescued. And that put her at peace and we told her that we can disappear tonight. And she gave us a little nod and we stood up and walked out and she jumped on the back of our motorbike and we disappeared into the night.”

That young girl became one of the 1600 children rescued by Destiny Rescue since 2011 and was settled into one of the organisation’s 25 rescue homes, where she was safely rehabilitated through a programme of education, vocational training, counselling and healthcare, spiritual guidance and, most importantly, love.

“Now she’s a happy little girl. Obviously she’s on a journey to being healed totally on the inside but now she’s got hope and she’s got a future,” says Kirwan.

“I can imagine what would I be willing to do if you were my daughter.”

Growing up in Cairns as a pastor’s kid, Kirwan always saw himself as a “giver not a goer” in his church because he was making money in his electrician business.

But that changed in 1998 when he started to talk about spending time overseas. At that time he had two young daughters and his wife wasn’t keen. Nor were his parents.

“So Dad thought it would be a good idea for him and me to head over to Cambodia and see a work that’s supported by our church. He hoped I would see that’s not how I want my family living. But I think God had other plans.

“We went through the slums in Phnom Penh where there is a lot of real in-your-face poverty – kids running around with swollen bellies and homes built over open drains. That really messed with me, seeing that first hand.

“I remember going back to my hotel that night and I was about to pray ‘God have mercy on these children’ but I didn’t even get those words out. I had the impression in my heart that what I really should be praying was ‘God have mercy on me if I don’t do something to help these kids.’

“That was the defining moment for me. I was called to do more and be more hands-on and I didn’t know what that was going to look like at that time.”

In July 1999 Kirwan and his wife went to Thailand to volunteer for their church.

At the end of 2000 he met an American passing through Bangkok, who told him he had been offered children that he could buy outright for $US400.

“That broke my heart and I thought ‘this is what I am really called to do,’ so in February 2001 we came back to Australia, sold up and launched Destiny Rescue in Thailand in October 2001.”

The charity now operates in Thailand, Cambodia, Laos, the Philippines, and the Dominican Republic with fundraising arms in Australia, New Zealand and the US. Kirwan’s second daughter plans to be part of the launch of an operation in Brazil next year.

“We genuinely believe we will start to see more kids being rescued than kids being lured into the sex trade.”

“Being a dad of daughters it speaks me very loudly and I’ve got a good imagination, so I can imagine how I’d feel and how far I’d be willing to go to rescue one of my kids. At some level, when I’m sitting in brothel with a 14 or 15-year-old child sitting next to me, I can imagine what would I be willing to do if you were my daughter.

“That’s why we do our absolute best every single time to rescue these girls.”

Kirwan says that on average 70 per cent of the girls they rescue stay out of the sex trade but he aims to lift that to 80-90 per cent over the coming years.

“I think one of our strengths is our willingness to change and try new things, to always improve. I’ve got three daughters and if I’m happy with 70 per cent that means I’d be happy with one of my daughters returning to the sex trade, which obviously I wouldn’t be.”

Asked if he feels Destiny Rescue is winning the fight against a trade that UN figures show entraps 1.2 million new children each year, he says: “I believe we’re winning the fight with each girl that we rescue. If we look at the size of the problem worldwide we’re having minimal impact at the moment, but if we look at each girl that we’ve rescued out of the sex trade – functioning ladies, holding down jobs, in healthy relationships, married with children – yes, we are winning the fight for those.

“We’ve proven over the years that we can rescue and rescue well and safely heal these kids and reintegrate them at a high success rate. It’s just a matter of us growing our team. So as our funding grows, as our team grows, we’ll be winning this fight, not just for the ones that we’ve rescued but we genuinely believe we will start to see more kids being rescued than kids being lured into the sex trade. It’s just a matter of time.

“That’s our vision, to end it in our lifetimes, and I’m not arrogant enough to think it’s going to be all Destiny Rescue but we hope that we are one of the ones who are leading the charge in seeing this evil end in our lifetimes.”