Acting Central Otago sub-area supervisor Detective Sergeant Derek Shaw said shooters would be moving through rural Central Otago and could notice something that might link to Mr Bates.
"We'd like them to be mindful that Chris is still missing and he's still being actively searched for.
"Please just let police know if there's any indication that Chris has been in the area where they're shooting or moving through."
He said signs could include discarded clothing or a phone.
If there was indication of Mr Bates, people should contact police immediately.
As for the search for Mr Bates itself, Det Sgt Shaw said police still had little indication or leads as to where Mr Bates was.
"We still have grave fears for his wellbeing and those fears have only increased as time has gone on."
Volunteer searchers had been out for about eight weekends in a row, some full and part-weekends, but had not been out for the last few.
"We're in a re-evaluation phase and we're looking for that indication which may come from duck-shooters in areas where they haven't been for some time, outside of our immediate search area," Det Sgt Shaw said.
"We haven't closed our minds to believing that Chris is just around the immediate Alexandra area, but he could be further afield.
"If that is the case, shooters outside our immediate search area, which was in the east and north of Alexandra, may come across something that indicates that Chris was or has been there."
Mr Bates has been missing since February 11.
