Maunu Four Square was robbed of cigarettes on March 5, while 1.2km away the owner of Maunu Superette chased an empty-handed robber who brandished what he believed to be a pellet gun on March 20.
The four robberies happened in just over three weeks in Whangarei.
Mr Huys said such violent robberies left the shop owners and their workers living in fear and police wanted to ensure them, and the wider community, that they were actively trying to catch the robbers. Police were keeping an open mind on whether the robberies were linked.
"Our main concern is that there have been a number of robberies occurring in those areas. We want to reassure people we are doing all we can to catch these people," Mr Huys said.
"We have increased patrols in the areas throughout the day. Our CIB team are following a number of strong leads in respect to the latest robbery of Otaika LiquorLand.
"We are also doing increased bail checks to make sure that those in those areas who are on bail are at home and abiding by their bail conditions."
He said the bail checks, and other inquiries, had resulted in several arrests of people who were allegedly wanted on warrants.
Mr Huys said while police were doing all they could, they also needed the help of the public.
"It's very important that if somebody witnesses any suspicious activity around shops, whether that be people seeming to case the place out, or unusual cars, or people acting unusually, please call 111 immediately and we will respond straight away," he said.
Officers have been visiting shop owners in the past few days giving them safety advice and Mr Huys said this was to help keep everybody safe.
"Although this type of information sharing with shop owners is something we have been doing for a number of years, we are really stepping it up in the affected areas and we will expand it into other areas."
Anyone with information on any of the robberies can call Whangarei police on 09 430 4500 or Crimestoppers on 0800 555 111.
