But, he said, only do so if the information can be gathered safely.
"We're a close community here in Whanganui, and it pays to know your neighbours and what's normal in your area," Grantham said.
Grantham said vehicle theft was a large contributor to the increase in crime.
This could include stealing number plates to be fixed to cars to commit crimes such as petrol drive-offs, or thefts of items from inside vehicles.
Vehicles parked up driveways and on the road were particularly vulnerable, Grantham said.
The increase in crime could be down to an increase in petrol and the fact that people were generally struggling, he said.
"We are also seeing thefts of items from around yards, such as pushbikes, scooters and lawnmowers," Grantham said.
Although the terms theft, burglary and robbery are often used interchangeably, they can mean very different things.
Theft is classed as taking someone's property but it can also be if someone enters a property that's not theirs and moves something from one spot to another.
Burglary is classed as breaking and entering and committing a crime, whether it be theft, vandalising or other crimes.
Like theft, robbery involves taking someone's property without the owner's consent but additionally includes the use of force or the threat of force.
Grantham said police now classed all of these events as "serious victimisations", as the effect on victims could be substantial due to the huge breach of victims' privacy and trust.
The New Zealand Police Crime Snapshot website compares a manually selected period of time with the same period 12 months earlier.
Theft had a 35.6 per cent increase from 1035 incidents to 1404 in the year to March 2022 compared to a year earlier.
In that period, burglary increased 2.1 per cent (671 up to 685) and robbery was up 5.1 per cent (39 up to 41).
Notable areas of increased crime were around central Whanganui and College Estate.
Grantham said while reported crime in Whanganui had increased over the last few years, it was important to note that so had the general population in Whanganui.
"This, therefore, brings some context to any increase in reports of this nature."
He said there were many ways the community could be more vigilant to help prevent theft.
"What I'd like to see is people taking measures to help limit chances for opportunistic thieves."
He said this included putting valuable items away in sheds and putting them under a decent lock, removing any valuable items from cars, and locking car doors.
Sensor lights were a relatively affordable deterrent which could help dissuade potential thieves, while CCTV could provide valuable information for police should something happen.
People could also look out for their neighbours and report anything that didn't seem right, Grantham said.
If you see anyone or anything suspicious, call police - if it's happening now, call 111 with as much detail as possible, or if it's something you notice after the fact, get in touch on 105.
