The arrest was made at an apartment in Darwin on Australia's northern coast, the Australian Broadcasting Corp. reported. Police found all the weapons, 12 semi-automatic pistols and two pump-action shotguns.
The weapons were taken from the armory of HMS Bathurst on Thursday night. A guard on the boat was assaulted during the theft.
Cmdr. Richard Bryson of the Northern Territories Police said investigators believe several people were involved in the theft. The suspect in custody has been identified only as a 40-year-old man, and Bryson said investigators are unsure if he participated in the theft and assault or was just holding the stolen items.