Police had received a complaint in July 2019 regarding allegations of indecent assault by the Korean diplomat in Wellington.
An arrest warrant was later sought and issued in February this year on three charges of indecent assault.
However, Kim had left New Zealand even before the complaint was made to police.
"Consideration had to be given to requesting the extradition of the alleged offender from his home country," Van Den Heuvel said.
"After carefully considering the evidence and legal advice, NZ Police has concluded that, while the standard of proof to prosecute the alleged offender and to seek a warrant of arrest had been met, the higher threshold required to initiate extradition proceedings has not been met."
Van Den Heuvel said the decision not to seek extradition has been communicated to the complainant, who was "disappointed" with the decision.
Police said in order to protect the privacy of all involved, no further comment will be made on the matter.