Police cordoned off Benge & Co Green Grocers the morning of the alleged robbery.

A grocery store manager who faked a robbery in Blenheim has been warned by a judge that he is facing jail time after "similar offending" in Auckland.

Thomas Damian Blake, 44, pretended he had been assaulted and robbed at Benge & Co Green Grocers, telling an elaborate story to coworkers and police.

But Blake had taken more than $8000 from the store safe himself, police later discovered, topping off several weeks of taking money from the till.

Judge Richard Russell said Blake was "no stranger to this type of offending" after a conviction in Auckland last year, shortly before he moved to Blenheim and became manager of the store.

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"You are in some serious trouble now and I need to warn you, prison is the likely outcome here, given your previous offending," Judge Russell said without elaborating on that offending.

He convicted Blake after he pleaded guilty at the Blenheim District Court on Monday and referred him to restorative justice, where he would try to make amends with the store owners if they were willing to participate.

Blake was responsible for opening the store on Grove Rd, ordering products and doing the daily banking, a police summary said.

SCOTT HAMMOND/STUFF Thomas Damian Blake's coworker arrived shortly before 6am to find him on the ground in the recovery position.

He earned more than $800 a week, but started taking extra money from the till in March.

The store's takings were down by $254.60 on the first occasion, and Blake deposited $120 into his bank account on the same day.

On the second occasion, about three weeks later, the store's takings were down by $137.30, and Blake deposited $100 into his bank account on the same day.

The amounts going missing from the till started to increase, up to $666 on one occasion in May.

Each time money went missing, Blake would deposit cash into his bank account, sometimes a day or two later, and sometimes split into two deposits.

Over a five-week period, the grocery store was missing $2645, and Blake had deposited $2315 in cash into his bank account in total.

SCOTT HAMMOND/STUFF Police conducted a scene examination and interviewed manager Thomas Damian Blake.

Blake arrived at work about 5.14am on May 21 and started opening the store.

He spent six minutes in the store room out the back, before taking an item out across the forecourt, and then he returned to the store and turned all the lights on.

His coworker walked into the store room about 5.52am and found Blake lying on the floor in the recovery position.

Police were called and were told Blake had been robbed. Police found $8977.40 was missing from the grocery store safe.

Blake was taken to the Blenheim police station where he gave an evidential statement recorded on DVD between 10.47am and 1.25pm.

Blake said he had been hit from behind and fell onto the concrete floor of the store room.

He saw a man wearing a black hoodie and a black scarf with white dots pulled over his face, Blake said.

He heard money being taken from the tills before hearing his coworker and the bread delivery person arrive, he said.

Police started investigating the robbery, sweeping the scene for evidence. They called for help from the public a few days later, hoping to identify a vehicle spotted in the area on CCTV footage about 6am.

SUPPLIED A green and silver Subaru was seen on Grove Rd shortly after the Benge & Co robbery.

But a week after the robbery, on May 28, Blake went to police and said a member of the public told him it was an inside job.

One of his employees was now too afraid to come to work, Blake said.

He signed a formal statement confirming the information was accurate, and that he knew it was an offence to give false or misleading information.

When confronted by police, Blake denied taking the money and faking the robbery.

He was charged with seven counts of theft by a person in a special relationship, and two counts of making a false statement to police.

Blake's lawyer Philip Watson said his client would struggle to pay the $11,622.40 in reparation sought by Benge & Co Green Grocers.

He had lost his job and the company was withholding his holiday pay, Watson said.

Blake was living with his mother in Kawerau, and she was paying for his travel to and from Blenheim for court appearances, so she could not loan him any money for reparation, Watson said.

However Blake would try to find work up north, Watson said.

Judge Russell remanded Blake on bail to September 10 for sentencing, ordering a pre-sentencing report to assess his suitability for an electronically-monitored sentence.