Nick Kinsella is leaving his role as head of the UK Human Trafficking Centre in Sheffield, which will be absorbed by the Serious and Organised Crime Agency (SOCA) from April 1.
The move comes at a critical time for the centre, with data showing that almost 60 trafficking victims are picked up in the UK every month.
The Yorkshire Post revealed last month that MPs had criticised the transfer to SOCA, raising fears that the centre's independence and expertise would be lost as part of a larger organisation.
But Mr Kinsella, who worked as a detective with South Yorkshire Police before focusing on human trafficking, said he was confident that its work would continue under SOCA, which has been dubbed the UK equivalent of the FBI.
"Change always presents challenges," Mr Kinsella said, "but this centre has already overcome some challenges.
"We have always had a very strong partnership with SOCA and we have members of SOCA embedded at the centre.
"I know that SOCA are committed to tackling human trafficking and the move represents some good opportunities."
Founded in 2006, the centre brings police together with officials from SOCA, the Crown Prosecution Service, HM Revenue and Customs, the UK Border Agency and non-government organisations.
Between April and December last year it helped deal with the cases of 527 victims, a quarter of whom were children.
Most victims, including 45 girls and two boys, were trafficked for sexual exploitation, but Mr Kinsella revealed that officers had also uncovered cases where people were to be used for domestic servitude, begging and forced labour.
Nigerian and Chinese nationals accounted for 30 per cent of cases, while 37 victims were UK citizens trafficked within their own country.
Mr Kinsella said: "Human trafficking is a really difficult crime to investigate because of the control the traffickers have over their victims, often through violence.
"Trafficking is not an immigration crime; many victims of trafficking are here illegally, but that is because they have been trafficked.
"They are not illegal immigrants; they are victims of crime."
Mr Kinsella added that he intended to continue supporting the battle against trafficking, despite his retirement.
He said: "This is a very demanding role, focusing on a crime that is a fundamental breach of the human rights of victims, and you become very driven to make as big an impact as you can.
"I suppose I will take a short holiday and I then intend to do some voluntary work, but it will be difficult not to keep involved in this type of work."