A Countdown spokeswoman said police informed the supermarket late last night and staff were working with police to help with the investigation.
"We have spoken with them today and understand an arrest has been made. Our thoughts are with the woman and her family."
Police said people were justified in using self defence of them or another when it was reasonable to use as according to section 48 of the Crimes Act 1961.
"This means you are allowed to defend yourself from attack, but use your common sense.
"The idea is to defend yourself, not to cause injury or get revenge. If you use unreasonable force, you are committing a crime."
Police said people's first concern should be for their own safety and that of others with them.
"Never take the law into your own hands or take unnecessary risks."
Hawke's Bay International Taekwondo Federation manager Ben Evans said these sorts of attacks can be prevented before they happen but a lot comes down to awareness.
Mr Evans who runs a self-defence class said no one should automatically think they're safe no matter where they were.
"You have got to have your guard up wherever you are, as things can happen out of nowhere."
He said body language and how one walks was vital in putting off an attacker.
"If you walk with small strides and look down you automatically come across as vulnerable and unsure. An attacker will prey on you as they will see you as an easy target."
"Instead people need to look up, look around and walk with confidence. Hold a poker face."
Mr Evans said if someone was grabbed they should respond by going for the weak link, the thumb.
Police are continuing to investigate the crime and are asking anyone who was in the area at the time who may have seen the victim, the alleged offender or his car, to come forward.
Information can be reported to Detective Sergeant Daryl Moore, at Hawkes Bay Police on 06 873 0531. Alternatively, anonymous information can be reported to Crimestoppers on 0800 555 111.