His lawyer Todd Simmonds said the decision not to lay any criminal charges "is the clearest possible indication that the allegations made against Detective Inspector Mark Gutry had no substance".
"Detective Inspector Mark Gutry is obviously pleased with the outcome of the criminal investigation and his intention at this point in time is to return to police duties as soon as is possible," said Mr Simmonds.
Superintendent John Tims, Counties Manukau district commander, said the allegation was treated very seriously.
"We rightly expect high standards of behaviour from our staff and we have robust processes in place to deal with such complaints.
"We have looked at this complaint thoroughly from a criminal perspective and will now consider it under the Code of Conduct.
"We are also working closely with the complainant to keep them informed of the steps we are taking."
Mr Tims said he was absolutely committed to ensuring that the issue is dealt with appropriately.
"I am unable to prejudge the outcome of the employment process and we will not offer further comment until this is completed." said Mr Tims.
Mr Gutry remains suspended.