A shopkeeper used a hockey stick to fend off an armed gunman who was holding a pistol to the head of a customer, the mother of "two beautiful, young children".

As the robber demanded cash from the till - "Give me money or I'll shoot her" - the dairy owner had other ideas.

Jayesh Amin, owner of the Farm Cove Superette in East Auckland, said he could think only of saving the woman, a regular customer who he knew had two children.

Mr Amin was preparing to close the shop at 7.45pm on Wednesday when his last customer approached the counter with a couple of icecreams.

At the same moment, a young hooded man ran in, grabbed the woman by the neck, shoved a pistol at her head and yelled: "Give me money or I'll shoot her."

For a couple of seconds, Mr Amin stood frozen. "I was shocked because it happened so fast. I didn't understand what was happening."

Another man came in with a metal bar and told the first offender: "Go ahead, bro, go ahead, bro. Shoot her, bro."

As the second man lunged across the counter, Mr Amin was too rattled to notice that a third robber had followed the others into the store.

Mr Amin took $600 from the till and held it up.

"I offered the money. I told them to leave the woman alone and take the money: 'Don't do anything silly - just leave the woman'."

But instead of reaching for the money, the three young men yelled further threats at the female customer.

"They should have come to me to take the money but they didn't," Mr Amin said.

"It was very hard to know what to do because I had shown them the money. My first priority was to save the woman. She was local and I knew she had two beautiful young children."

So Mr Amin reached behind the counter for a hockey stick he had there and swung wildly at the three men.

He struck one, then ran around the counter towards the man with the gun.

The three men scurried out the front door.

"I think they got a little scared," Mr Amin said.

Police were quickly on the scene - Mr Amin's wife saw the incident on a security camera monitor in their upstairs residence, and called 111.

Two teenagers have been arrested for the robbery and appeared in court yesterday. Two others - one the driver of a getaway car - are being sought.

Last night, Mr Amin said he was still shaking because of the ordeal.

"I'm so tired. I couldn't sleep all night," he said. "From yesterday morning at seven, I haven't slept. I was so scared."

The drama did not end with the robbers running out the door.

Mr Amin chased them outside and called for help. The owner and chef from the next-door restaurant came to his aid.

The three robbers then ran to a car driven by a fourth man and sped away - only to be pursued by a member of the public.

The man chased the offenders until they stopped the car, got out and one pointed the gun at him.

As the man tried to flee, his rear windscreen shattered.

Police say they are exploring several possible reasons for the window breaking, and have not confirmed that it was caused by a gunshot.

The four offenders abandoned the car, and police later found an air pistol in it.

The two men arrested are aged 17 and 18 and appeared in the Manukau District Court yesterday on charges of assault with intent to rob, threatening to kill and commission of a crime with a firearm. Further charges may follow.

Police said that the store owner and the customer escaped serious injury but had been extremely shaken by events and were being counselled by Victim Support.

Detective Senior Sergeant Albie Alexander said criminal investigation branch staff had examined the premises and were following "very positive" leads regarding the identity of the two missing suspects.