Members of the Bomb Disposal Unit have a cache of explosives, ammunition and ivory at an address in Durbanville near Cape Town on Saturday.
Police say they responded after being called by the son of a man who died earlier this year.
The deceased previously worked for arms manufacturer Denel.
Western Cape police spokesman Captain FC van Wyk said: “The members also found ammunition, two elephant tusks and a stack of explosives.”
Police say the discovery is not linked to gang activities in the Western Cape, however they are investigating it.