The misbehaviour of 200 to 300 youths on Saturday was the only major incident the police faced on Australia Day.
The youths were hanging around the bus station on Haley Street from around 8pm to 11pm.
“They were exhibiting disorderly and anti-social behaviour,” Bunbury Sgt Phil Nation said.
“Most did move on when told, but there were a few who did obstruct police. Australia Day is one of those days when we get big groups of youth and it’s always disappointing we have to deal with them at a family event.”
On Australia Day, there were only six arrests, five for disorderly behaviour and one for exceeding 0.08 blood alcohol content.
“We did 46 random breath tests on Australia Day and that was the only one that blew over,” Sgt Nation said.
Seven move-on notices and 17 liquor infringements for street drinking were handed out.
“There were no liquor infringements at Back Beach at all,” Sgt Nation said.
“There was a shark sighting in the morning that closed the beach for a couple of hours.”