They then forced the young man to walk in front of them while they checked in each room to see if anyone else was there.
After they had made sure there was no one there they cut the padlocks into the shop and stole all the cigarettes and other items.
The dairy owner was not sure what else had gone as police would not let him into the shop until they had examined the scene.
Ransacked house
Once the men had taken what they wanted from the shop they then ransacked the house including his son's room, the man said.
"They took his computers, his paintball equipment. They ransacked my office and took some money, then beat him again and took off with his car."
He said in the early hours of this morning his other son was driving through town to be with other family members after the robbery when he saw the stolen car pass by.
He gave chase but the occupants sped off so fast he couldn't keep up.
The police discovered the car in Alma Rd this morning stripped and burnt out.
The dairy owner said the robbery was "cowardly bloody bulls*** and they needed to be caught".
His son "wasn't too bad" but the reality of what happened would probably sink in later.
In June of this year thieves broke into the dairy and made off with cash and tobacco. No charges have been laid in relation to the theft.
Investigation
Police said they were investigating an aggravated robbery at the Mill House Dairy last night.
They said the offenders were all wearing bright orange vests or jackets and one of them was described as having very blond hair.
A police spokeswoman said they were conducting a forensic scene examination at the dairy this morning and wanted to hear from anyone with any information.
"West Coast Police would like to reassure members of the public that they are actively working on locating the offenders and holding them accountable."
Anyone who has seen anything suspicious in the area, or with any information, should call Detective Sergeant Kirsten Norton on 021 191 5738 or call Crimestoppers anonymously on 0800 555 111.
- Westport News