National security police said on Friday they had arrested two people on suspicion of possessing a handgun and bullets without a licence.
Officers said they raided a couple’s home in Pat Heung in the morning.
A pistol, 92 bullets, gas mask and various weapons were seized, police said.
Senior superintendent Steve Li from the force’s national security department said the suspects, aged 32 and 36, were believed to be couriers.
He said detectives would be looking into where the weapons came from.