Two police officers and two cab drivers were attacked in a large brawl outside Palmerston North Hospital's emergency department on Wednesday.
A cab and another vehicle were involved in a minor collision on the hospital grounds this morning.
The car's occupants then attacked the cab driver, along with another cabbie who was nearby and became involved.
Witnesses described the attackers as being gang members.
Police were called and two officers arrived, but a witness said they were quickly overwhelmed by up to 14 people.
The cab driver involved in the crash was taken to the emergency department and "hidden" from the attackers who were threatening to kill him.
"There was shouting and swearing. It was violent and the police were beaten up," the witness said.
"Their police car was attacked too. It was frightening and disgraceful."
Six other police cars arrived soon after and the witness said officers deployed pepper spray and a taser to end the altercation.
The government provided extra security to the highest risk hospital emergency departments over the summer as part of its 100 day plan, but the number of round-the-clock security guards at some EDs was reduced in April this year.
In response, police said they took one person into custody, but had no information about officers being attacked, or a taser and pepper spray being used.
Te Whatu Ora said no one was hurt.
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