A 44-year-old man and a 57-year-old woman were arrested on Sunday following a search at a house in Broom Close in Twinbrook.
Items recovered from the house included 700 rounds of assorted ammunition and seven mercury tilt switches.
A detonator cord, firework powder and assault rifle magazine were also found.
Det Insp Philip Montgomery said: "We believe this is a significant find because it has taken off the streets materials designed to kill and injure."
Although the searches took place at the weekend, police have just released details and photographs of what was found.
Det Insp Montgomery said the items were concealed in a bag in the roof space.
He said: "Inside the brown paper bag were more than 700 rounds of assorted ammunition packed into items of clothing, plastic bags and containers."
Officers later searched another property at Glenwood Walk in Poleglass and several items have been taken away for detailed examination.
Det Insp Montgomery said: "We are not in a position at present to disclose what we have found there."
He also apologised to local communities who were inconvenienced by Sunday's searches.
"I am sure the overwhelming majority of people in these communities are thankful that such items have been prevented from causing harm.
"We will continue to work with communities to reduce the threat posed by those involved in such activity and would ask people to contact police if they have any suspicions about terrorist activity."
Bomb-making components and ammunition have been seized during searches in west Belfast as part of a dissident republican investigation.