"The kids were saying a man at the house had flipped out and chased them down the road saying he was going to shoot them all," Ms Parker said.
Her son told her he had been hit in the chest by a man and Ms Parker made a point of telling the officer at the scene to record her son's details in his notebook.
"The officers there really didn't seem to show a lot of care and did not follow procedures with the mention of a weapon," Ms Parker said.
She said it was now seven weeks since the incident. Her son had been interviewed four days after the alleged assault but there had been no update.
In a brief written statement, Area Commander Whangarei Kaipara Inspector Justin Rogers said an investigation into the incident and alleged assault was ongoing and a number of people who were at the party were yet to be spoken to.
Mr Rogers said a complaint regarding police actions on the night had been received and was being dealt with through the complaints process.
"Any issues regarding police actions that arise from the investigation will be addressed as an employment matter."
Police did not answer questions about the claims a senior police officer on duty at the time went to the party, collected his son and then left. Nor did they answer questions about how police dealt with the situation or if the man who allegedly threatened to shoot the partygoers and assaulted a teenager had been interviewed.
Ms Parker has lodged a formal complaint against the police, citing they had not treated the threat of a firearm seriously, failed to call for back-up and a senior policeman took his child and left.
She said the party had been well organised with written invitations required before the guests could enter. The amount of alcohol they brought was also checked.