Another officer then dragged the woman by her leg across the car park where she was restrained by two more officers.
Doak then used his Taser for a second time by holding it near the victim's head while she was lying on the ground restrained to intimidate her into giving up the identity of the fleeing driver.
Doak again used his Taser for a third time by arcing it while the handcuffed woman sat in the back of a police patrol car.
Authority Chair, Judge Colin Doherty said: "The officer's actions were inappropriate, oppressive and threatening to the woman. He failed to act in a manner that would be reasonably expected of a police officer."
The IPCA also found it was unnecessary for the woman to be dragged across the car park.
Doak was charged over the incident and faced a trial last August.
At trial, the young woman, Mary Jane Takerei, told the court she begged police to stop hurting her as she lay handcuffed before Doak allegedly pressed a Taser between her eyes.
"What's his f**king name or I'll f***ing Taser you!"
Takerei said the threat was made by Doak after she was dragged from the car.
Other officers testified that Takerei hit Doak's partner Constable Florence Roberts in the face with spray from a CRC canister.
A jury returned split verdicts and found the 26-year-old not guilty of assault with a weapon but guilty of unlawfully presenting a restricted weapon.
Despite arguments from Doak's lawyer that he would likely lose his job, Judge Noel Sainsbury convicted the constable.
The decision of Judge Sainsbury, who said New Zealanders "expect better" of police officers, was then appealed to the High Court and a hearing held in June.
In July, Justice Simon Moore granted the appeal and quashed Doak's conviction.
Takerei complained to the IPCA about the force used against her during her arrest and that officers refused to provide her with pepper spray aftercare, refused to take her home if she did not answer questions, behaved unprofessionally and used inappropriate language during the incident.
In a statement issued by police today, they acknowledged the findings of the IPCA.
"The use of Taser by one of the attending officers was subject to a criminal investigation into this incident and the officer was subsequently prosecuted.
"That court case has now concluded with the officer being found guilty of presenting a restricted weapon and receiving a discharge without conviction on appeal."
Auckland City District Commander Superintendent Karyn Malthus said police agreed with the findings that Doak's actions were unjustified.
"I believe police has shown by our actions in charging the officer that we do not accept the type of behaviour that was shown during this incident.
"It was well below the standard our community expects of us and completely out-of-line with our police values.
"This matter was brought to police's attention by another officer and I commend them for coming forward so it could be fully investigated."
She said Doak remained working for police on restricted duties and the employment investigation was ongoing.
"For this reason, we are not in a position to comment further."
