The summary of facts revealed Martin entered the bank about 1.57pm on May 15 wearing a black cap, a black top pulled over his head, and carrying a backpack.
He said to the female bank teller "I need $20,000".
She replied she would need to check how much cash she had in her drawer and asked to see Martin's identification and bank card.
Martin replied, "No, this is a robbery and I have a gun" and gestured to his hands both inside his top before he made a further gesture with his hidden right hand.
The teller immediately pressed the alarm bottom before she handed over $2660.
Martin put the money into his pocket, saying to the woman: "Thank you, but I'm sorry I need the money for my son's procedure," then calmly left the bank.
He hopped into a taxi and handed the driver $60 asking her to drive him to Putāruru.
About 8.40pm on May 25, Martin, again wearing a hooded top, approached a Burger Fuel worker who was putting rubbish in a skip bin near the 12th Ave store.
Martin told the male worker: "Take me to your store or I will shoot you in the leg."
The young man told Martin there were a lot of staff working at Burger Fuel when he asked how people were inside the store that night.
After the worker returned to Burger Fuel, Martin went into the nearby Subway store.
He again claimed to have a gun and demanded the Subway worker open the till.
Martin fled with $465 chased by a second Subway staffer and drove off in a vehicle.
On May 29 Martin also tried to open a cash register at Tauranga Central Backpackers on Willow St and he was located a short time later inside the Tauranga Library.
Martin told police he robbed the Subway store to feed his methamphetamine habit and admitted he smoked at least one gram of the drug daily.
Judge Thomas Ingram further remanded Martin in custody for sentencing on September 3.