South Australian police are continuing their search for the leaders of an international doomsday cult after they uncovered a stockpile of weapons and explosives during raids of the group's compounds yesterday.

About 90 police searched 12 properties in Adelaide used by Agape Ministries, finding guns, fuses, detonators, detonator cords and 20,000 rounds of ammunition - some of which were hidden in the steel frames of bed-heads.

But Superintendent Jim Jeffery of South Australian Police's Commercial and Electronic Crime Branch said it was not yet known why the group was amassing weapons.

"The reason for stockpiling and hiding this ammunition clearly needs to be ascertained," Superintendent Jeffrey told reporters yesterday.

Four men were arrested and charged with firearms offences, but police are still hunting for the leader of the sect, Rocco Leo, and two other senior members.