The panic alarm had been installed by the shop's owners following an armed robbery in 2009, as well as CCTV cameras which have enabled police to gain a detailed description of the woman.
In 2009 a male made away with cash and cigarettes after flaunting a knife and a similar robbery, this time involving a toy gun, occurred at the store last year.
Detective Sergeant Darryl Brazier said the disguised woman - aged between 17 and 25 - walked into the store and demanded money, but was spooked by the alarm and fled on foot.
"A female walked into the shop and presented a knife and ... threatened to stab [Ms Savage]. She is described as a female of heavy build wearing a purple or dark-blue coloured t-shirt [and] black baggy pants. She had a blue bandanna covering her hair, with white polka dots. She also had a pink-coloured bandanna covering her face and she was carrying a black backpack.
"She had a white bandage on around her left hand. She had the knife in her right hand, it's very long-bladed, almost like a bayonet-type knife - possibly up to 10-inches long,'' he said.
After her foiled robbery attempt the woman was seen by witnesses fleeing the scene on foot, heading up Kaimanawa St.
After displaying the knife, Ms Savage said the woman had dumped the bag on the counter and demanded it was filled with money from the till.
Ms Savage backed away from the counter when she saw the knife, putting almost two metres between the pair.
"I got a fright. I'm not scared to admit that. [At first] I thought it was a joke ... then I saw the knife and back I went out of her reach. I'm rather proud of me, my survival instinct kicked in, it was basic gut reaction to get away from the knife. It was an impressive knife,'' she said.
"She reached out and smacked the till with her bandaged hand, trying to make it open. I pushed her hand away but I don't remember doing that until I saw the video. There was no way in hell I was giving that [woman] money. She didn't get what she wanted and I hope to hell she got a fright because I didn't cow to her.''
Mr Brazier said the calm actions of the eight-time grandmother were enough to scare the would be robber off.
"Obviously we want to apprehend this woman before she does it again. Clearly she is desperate. We are looking for anyone who might know this woman, or anyone who may have seen this woman running down Kaimanawa St. It appears there was no vehicle involved - she is the only person we are looking for in relation to this,'' he said.
Anyone with information on the woman or the attempted robbery is asked to call Tauranga Police on (07) 577 4300 or Crimestoppers on 0800 555 111.
