In that incident, the offender, who obscured their face with a bandanna, stabbed the male attendant at Mobil Oxford St and stole cigarettes before fleeing the scene about 4.30am.
The attendant was recovering at Palmerston North Hospital from injuries that were not life threatening. A 21-year-old Levin man was arrested in relation to the incident.
On Saturday, a dairy owner was robbed at gunpoint at the Nancy Ave dairy in Mairehau, Christchurch.
The masked robber apparently waited until owner Bankhaj Patel's wife was alone in the shop before coming in with a gun.
"He pointed the gun to my wife, asked for ciggies and just walked away," Mr Patel said. The thief also made off with cash.
On Friday, three men, one armed with a screwdriver, robbed a liquor store in Taupo.
The group threatened the store worker and took off with money, cigarettes and alcohol.
Northland police are now calling for information on the latest incident.
"Police need to apprehend the offender to prevent any further violent crimes by him and before any person is seriously injured," police said.
"Anyone who sees the offender is not to approach him, but to contact police."
The offender was described as 1.7m to 1.8m tall, of thin to medium build. His age was unknown.
He was wearing a grey-coloured hooded sweatshirt, a white peaked cap, sunglasses, grey long trousers and sports shoes. He possibly had a red bandanna around the lower part of his face and neck.
Police would like to hear from anyone who saw suspicious activity in the area at the time. They are particularly keen to speak to two men seen driving a beige or tan coloured twin-cab ute in the area at the time.
Anyone with information should contact Detective Sergeant Jonathan Tier of Dargaville police on 09 439 3400 or Crimestoppers, anonymously, on 0800 555 111.
