On their second day in Southeast Asia, Petra Bagust and Ido Drent head to Chiang Mai in the north of Thailand.
Drent says the city is notorious for paedophiles operating in the area.
On their way to the city, both admitted to feeling overwhelmed by the sheer size of the human trafficking industry which Tearfund claims is rife in Southeast Asia.
Human trafficking is an organised criminal activity that uses deception, coercion and force to transport and harbour human beings for the purpose of exploitation.
According to Tearfund, 21 million people are trapped in slavery today, more than at any other time in history, 4.5m people are trapped in forced sexual exploitation and US$99 billion (NZ$136b) is earned through sex trafficking and exploitation.
"The problem is big. The way this industry is set up is it's set up to dehumanise the people - not respect their humanity," Drent said.
"Part of the problem is that it all feels so overwhelming because we're not connected to the individual, but there are individuals who are survivors - and they count, they matter.
"We can bring hope to them."
Bagust said despite the scale of the problem, women did make it out of slavery and made their way home.
Last year, money raised through Tearfund's Live Below the Line campaign helped the organisation's partners rescue 54 victims of human trafficking, and convict 26 offenders with a total of 244 years of jail time.
Drent and Bagust are sharing daily video diaries of their journey through Thailand and Cambodia with the Herald, ahead of their participation in this year's Live Below the Line challenge, which will see them eating on NZ$2.85 a day from September 19 to 23 and raising money to fight human trafficking.
According to Tearfund, the average age of victims trafficked into prostitution is 12 years old and people living below the international extreme poverty line (on NZ$2.85 a day or less) are most vulnerable to being trafficked.
Kiwis can join Bagust and Drent by signing up to do the challenge at www.livebelowtheline.org.nz