The mother of a Christchurch mosque attack victim has been left shaken after being dragged across the floor of the dairy she was working at in an aggravated robbery.

Police are asking the public for help to find two men who allegedly entered the Springs Rd dairy in Christchurch, threatened and assaulted the woman before leaving with cigarettes at 7.30am yesterday.

The Herald has spoken with her son, who also works at the dairy, but did not want to be identified.

"It was my mother who was involved. She is very shaken. She was dragged across the floor of the dairy."

It appeared as though the offenders were carrying a gun at the time, he said.

He said they have had incidents at the dairy in the past but not like this.

"We haven't had any incidents where somebody has put hands on someone."

It is another blow for the family after losing their beloved son and brother in the Christchurch mosque attacks.

The dairy's owner Junaid died at the Masjid Al Noor mosque in Deans Ave during the shooting on March 15, 2019.

He left behind his wife and three children under 5 years old.

"It feels like very much like one incident after the other. We just have to work through it, get through it.

"We have to deal with the negative things that happen. It's been a very tough time for our family," he said.

The man said his mother was resting at home on Tuesday after the incident.

"She is just trying to process and digest what has happened."

Anyone who was travelling in the area or saw two men dressed in black leaving the scene on foot are urged to contact police.

It is understood the offenders got into a black Audi A3 parked on Amyes Rd and drove away.

"Police are determined to hold these men to account and will not tolerate this type of offending in Christchurch," a spokesperson said.

Greater Hornby Residents' Association member Marc Duff said it is incredibly sad and their thoughts go out to the family.

"It's horrible the way people keep hitting the dairies. When you ram-raid a dairy or do an armed hold-up, you're effectively hitting at the heart of the community," he said.

Anyone with information that can assist police in their inquiries into this incident is urged to contact 105 and quote 220613/4102.

Alternatively, information can be given anonymously via Crime Stoppers on 0800 555 111.