"In the past 10 years, there's been a big escalation in the number of people in the street prepared to have a go at police officers."
Mr Shadbolt believed policing was becoming a more dangerous profession as a result.
"Police are dealing with a lot more unpredictable behaviour than they used to - drug use and mental health issues factor in that.
"Officers are generally able to talk to people in the first instance but, in some cases, especially those affected by alcohol and drugs, situations can evolve very quickly."
The most assaults of Wanganui officers was 51 in 2011, and the least was 23 in 2005. Last year there were 41 assaults.
Mr Shadbolt said the association was pleased access to Tasers and firearms, and training had improved - but believed more could be done to protect officers.
"It's extremely unlikely for an officer to go through their career without being assaulted. We need to keep pushing safety and training, and getting new and better equipment.
"Tasers in particular are very good in escalating situations but there's rules about when you can carry them. The association thinks there should be a change in policy to allow officers to carry them at all times."
Nationally, there were between 1614 and 2574 assaults on police each year in the past 10 years. The highest number of assaults was in 2009, while the lowest number was last year.
Over the 10-year period, assaults have taken place at a rate of more than 40 a week.
In the past five years, the number of assaults dropped by more than 26 per cent, while injuries as a result of the assaults fell by almost 30 per cent.
Serious assaults on police were also declining, Assistant Police Commissioner Mike Rusbatch said. "This reduction has not happened by chance," he said.
"Police take the safety of its staff seriously and work very hard to ensure they are well trained, equipped and supported to carry out their jobs.
"In recent years, this has included the roll-out of improved tactical training, the introduction of stab-resistant body armour, greater access to tactical options such as Taser and firearms, and the introduction of officer safety alarms for those working in remote areas."
Any violence or assault on staff was unacceptable, he said.
"Tactical training is also heavily focused on officers using their judgment and the de-escalation of violent situations with force that is appropriate to the situation.
"This means the vast majority of incidents are resolved peacefully.
"We also continue to review critical incidents to ensure our tactical responses remain in line with best practice, and to identify any lessons that can help us ensure our staff and the public continue to be kept safe."
