Nurses in emergency departments aren't bothering to report assaults on the job as it's too complicated and too time-consuming.

A new study, published in the New Zealand Medical Journal, claims many assaults in the department go unreported, particularly when stressed and overworked nurses are the victims.

READ MORE: Nurses: We shouldn't have to put up with violence to do our jobs

Massey University nursing professor Jenny Carryer told Mike Hosking reporting assaults is tricky territory as there has to be time to investigate.

"When people are caring for people, the basic reaction is compassion and care and reporting someone for violence cuts across that."

LISTEN ABOVE AS JENNY CARRYER SPEAKS WITH MIKE HOSKING