The sources said the policewoman was arrested after the arrival of on-duty police. Police headquarters confirmed she has been stood down pending criminal and employment investigations, but police were not releasing further information.
Police Sport boasts a membership of 4700 from current and former police staff and is said to be the largest employee-based sports organisation in New Zealand.
It is funded by $3.50-a-week payments from members, with funding also from the police association and other sources, while the employer, the New Zealand Police, provides what the Police Sport website calls "material support."
An earlier version of this story incorrectly stated the incident involved an altercation between a woman and Thirsty Whale bar owner Chris Sullivan and another woman had to intervene.
A spokesperson for Mr Sullivan says he only became involved at the periphery when assisting other people involved in the incident.
The earlier version of the story included a caption which suggested the assault was inside the bar - this is not correct.