According to a report by Jane's Defence Weekly to be published next week, the missiles range is officially 250km and can reach neighbouring capitals such as Damascus and Beirut with ease.
But Israeli defence sources on Tuesday said its range is actually "well beyond 300km". An additional boost engine was the key to making the adaptation possible.
Yossi Aviram, marketing director for Israeli Military Industries, said: "It is an advanced, high subsonic, long-range loitering strike missile for the search, acquisition and precision attack of high value mobile, fixed and relocatable targets."
The cruise missile is also able to loiter above a target area before engaging targets with a choice of 30kg warhead payloads.
It can use a variety of infrared and electro-optic systems to pinpoint enemies up to 16km away and can select its own targets.
"It is an advanced, high subsonic, long-range loitering strike missile for the search, acquisition and precision attack of high value mobile, fixed and relocatable targets"
marketing director for Israeli Military Industries
In addition to converting the Delilah air-to-surface missile, other reports suggest that Israeli industries are exploring the possibility of converting Rafael's AGM-142 Popeye III as well as the Gabriel 3 anti-ship weapon into land-attack missiles, both providing a range of up to 300km.
Israel has been seeking to obtain land-attack cruise missiles for almost a decade.
According to Jane's, the US government has twice denied Israeli requests to purchase the Tomahawk land-attack cruise missile forcing Israel to turn to domestic production.
However, Palestinian security officials have often questioned unofficial military hardware cooperation between Washington and Tel Aviv.
Before taking office, the Under Secretary of Defence, Douglas Feith, confirmed that he “represented a leading Israeli armaments manufacturer in establishing joint ventures with leading US aerospace manufacturers for manufacture and sale of missile systems, to the US Department of Defense and worldwide.”
Unconfirmed reports also suggest that Israel Aircraft Industries is developing a longer-range cruise missile that could be deployed from the Israel Navy's Dolphin-class submarines.