A person who tried to stop two alleged offenders after an aggravated robbery is believed to have been hit in a the head with a brick for their efforts.
The Mako Mako Rd dairy in Levin was robbed - for the second time this year - on Monday.
Two people, understood to be a male and a female, both young, entered the Mako Mako Rd dairy just before noon and threatened staff with a knife.
A panic button was activated and the alleged offenders fled the scene, before being arrested by police a short time later.
Police initially said no injuries had been reported, but later confirmed they were aware of someone being assaulted when a person attempted to stop one of the offenders.