A man who police said turned up at the Napier Courthouse last Friday morning to face an assault charge was locked up after he intimidated four people in the foyer.
It is understood one of the four was a victim associated with the case for which the man was attending the defended hearing.
"This is something we take a very hard line on," Napier Police Senior Sergeant Sarah Stewart said.
"Police treat any interference with witnesses very seriously."
The man, who has gang associations, was seen to enter the foyer and approach the group.
One witness said the man appeared to have his fists clenched as he spoke to the group.
Police arrested the man and charged him with attempting to pervert the course of justice. He was remanded in custody.