A masked offender armed with what appears to be a machete robbed Hampshire Street Dairy in Aranui shortly after the female owner arrived at the store.

The robbery happened about 5am, leaving the owner shaken. No one was injured.

Security footage shows the offender behind the counter, gripping the large blade while handling an open till drawer.

They were wearing a black hooded top, black trousers and a blue patterned face covering, and carrying a red bag.

The owners said the offender wore Nike TN shoes and fled on a purple bicycle.

They were appealing for nearby residents to check security cameras and doorbell recordings for footage from around 5am.

Anyone who recognised the offender or had relevant footage was urged to contact police.