David's Sling, designed to shoot down rockets fired from 100 to 200 kilometres away, will be the final piece of a shield that already includes short-range Iron Dome and long-range Arrow-2 and Arrow-3 missiles.
"In the next two weeks we will declare the David's Sling to be operational, and at that time we will have completed our multi-tier (defence capability)," said the officer, who could not be identified under military rules.
"I'm sure that together with the Iron Dome and the Arrow-2 and Arrow-3 it will enhance our ability to deal with threats," he added.
Israel used Iron Dome extensively to intercept rockets fired by Palestinian militants in the 2014 Gaza war, and the Arrow missiles were developed with an Iranian missile threat in mind.
David's Sling, developed and manufactured jointly by Israel's state-owned Rafael Advanced Defense Systems Ltd. and the US Raytheon Co., would likely be used to intercept projectiles fired by the Iranian-backed Lebanese guerrilla group Hezbollah, which last fought a war with Israel in 2006.
The Israeli military said it used an Arrow-2 on Friday to destroy an anti-aircraft missile fired from Syria after Israeli aircraft carried out strikes there.
Israel has mounted dozens of air raids to prevent weapons smuggling to Hezbollah, which is fighting rebels alongside the Syrian army. However, the interception of a missile making its way over the Syrian border was an uncommon incident.