The Authority was unable to determine whether the officer punched the woman because of conflicting accounts given by each of them and inconclusive medical evidence.
"When restrained in a police car following her arrest, the woman took off her seatbelt and kicked the officer in the face after he took his attention off her to make a phone call," said Authority chairman Judge Colin Doherty.
"The officer said he acted in self-defence by pushing the woman backwards and pinning her against the inside of the car door, restraining her head against the window.
"The Authority found that this was a justified and proportionate use of force in these circumstances."
Police officers are justified in using force provided it is reasonable and proportionate, which the IPCA ruled it was in this instance.
"Our officers are faced with situations like this every day, and must make constant assessments about using the right tactical options to keep themselves, their colleagues, members of the public, and the person they are dealing with, safe," said Hawke's Bay Area Commander Inspector Jeanette Park.
"We are pleased the Authority agrees with our officers' accounts in that the force used was justified and proportionate for the situation."