Supt Basham will shortly pack up his desk in Dunedin and relocate to Police National Headquarters in Wellington after securing a promotion.
His seven-year stint in the south makes him one of the longest-serving Southern District Commanders in memory, police said.
His role will be filled by Supt Jason Guthrie while a new permanent commander is appointed.
“I am profoundly grateful to all the Southern staff I’ve had the pleasure to work alongside for their professionalism, their resilience and dedication to duty, and their kindness along the way," Supt Basham said.
In his new role as Assistant Commissioner Investigations, Supt Basham will draw on his experience of criminal investigations at home and abroad, police said.
After joining New Zealand Police in 1985 and being stationed in Counties Manukau, Supt Basham joined the Criminal Investigation Branch (CIB) in 1988 and qualified as a detective in 1991.
In 1998, he gained international experience when he took up a position in the Netherlands as a war crimes investigator with the United Nations International Criminal Tribunal for the former Yugoslavia.
Living in Holland, but working principally in Bosnia Herzegovina and travelling all over the world, Paul describes this time in his career as 'life-changing'.
He remained with the War Crimes Tribunal for five years, returning to New Zealand Police in 2003.
He told the Police Ten One Magazine his most recent lasting legacy would be his time in Dunedin after moving there in 2017.
“Moving to Southern was an opportunity for my family and I to live and work in the mainland, which was a big part of the attraction for the role, and we certainly have made the most of the experiences that living in this part of Te Waipounamu can offer.”
He will begin his new role in late March.
