Matangi's 40-year-old brother-in-law was hit in the face about five times as the men demanded the keys to the gun cabinet.
Matangi said his 72-year-old father-in-law then biked a short distance to Matangi's house on CB Farm Rd, at 7.15am.
The elderly couple were "fine, just a bit shaken" and their son had a cut to his face and a swollen eye, he said.
"After the offenders left the property one of the victims managed to free themselves and call police," said Detective Sergeant Peter Vine.
Police said the offenders took cash, two rifles, a shotgun, ammunition, personal effects, and one of the victim's vehicles.
"We believe the offenders arrived at the property in a vehicle and left in this vehicle and the victims'," said Vine.
"We cannot disclose at this stage the amount of cash that was taken from the property."
The victim's vehicle is a 2009 Black Holden Colorado, registration EZP335.
Anyone with information is asked to contact the Levin Police Station (06) 366 0500 or call Crimestoppers anonymously on 0800 555 111.
- nzherald.co.nz