A pregnant woman was the ringleader of a group – with a child in tow – that allegedly robbed and threatened a fellow pregnant shopper at a Hamilton supermarket, a court has heard.

Stevie Karaitiana-Turnbull, now 23, pleaded not guilty to two charges of aggravated robbery before a jury at Hamilton District Court yesterday but was painted as the ringleader by the Crown and witnesses who say she even tried to tear a phone from a store worker who filmed their getaway. Her lawyer says she was falsely accused.

In September 2009 Karaitiana-Turnbull and three friends – one of whom was said to have had a baby with her – entered Woolworths supermarket (now Countdown) in Rototuna.

While a "noticeably pregnant" woman was getting icecream from a stand-up freezer, one of the group allegedly snatched her purse from her basket.

The person with the purse left the store almost immediately and the rest of the group were confronted by the victim.

She asked for her phone back but was allegedly met with a fiery response from Karaitiana-Turnbull, who appeared to be the leader, she said.

The incident was seen by the staff member who watched the events take place through gaps between the shelves in the adjacent aisle.

"You didn't see nothing bitch," he reported them saying to the victim as they walked away. The victim followed the group down another aisle as she looked to alert a manager, and moments later another argument took place, where Karaitiana-Turnbull allegedly threatened the victim.

"They said, `You f***ing bitch, we'll take you outside ... it's because we're black, we always get this. We're just in here to shop."'

"I was pregnant at the time and didn't want to put myself in any danger," the victim said.

As the exchange became more heated the women left the shop and were pursued by the male staff member and another female employee.

The man told the jury he filmed the group on his cellphone as they got into a car, until they noticed him. Karaitiana-Turnbull allegedly approached him and demanded the phone, which he had slipped ino his pocket.

When it became clear he was not going to give it up, he said she started ripping at his pocket but as he tried to fend her off others joined in.

As he fell to the ground the phone spilled out, was picked up by one of the women, who bashed it on the ground and threw it into the car.

While his female colleague tried to stop one of the assailants getting back into the vehicle, he jumped on the bonnet to stop them leaving, but eventually got off to help his friend.

Bystanders saw the melee and reported the licence plate number to the police.