In the July incident, a woman working at the Brookfield dairy was held at gunpoint by a masked offender, who demanded cash.
She refused to hand cash over, and was reported to have accused the man of using a fake gun.
In the latter incident, two men were reported to have entered the Busy Bee Dairy, armed with a baseball bat and a hammer.
The men, described as Maori, stole cash, cigarettes and tobacco as well as causing some damage to the store, the police statement read.
Both men were wearing dark clothing and had dark scarves over their faces.
One of the men was thought to be aged between 18 and 20 years old and had a small amount of facial hair.
Detective Senior Sergeant Greg Turner thanked the community for their help solving the crimes that have resulted in arrests.
"Good old fashioned detective work went into solving these robberies and we would like to thank the community for coming forward and helping us solve these offences."
If anyone has any information in relation to the remaining unsolved robberies, they are encouraged to contact Crimestoppers anonymously on 0800 555 111