Israel is to delay the deployment of its "Iron Dome" multi-million-dollar missile defence system until next year, a military source said on Monday.

The defence ministry had said in July that the Iron Dome interceptor, designed to combat rocket threats from the Gaza Strip and Lebanon, would become operational in November.

But the source told AFP the military had now decided to put back its deployment until the first quarter of 2011, to allow more time to train those operating the highly complex system.

"This system is unbelievable," one officer told the Jerusalem Post. "It is, however, sometimes a complicated process to take in such a system and turn it into a fully functioning weapons system."

In the meantime, the system will be stored at an air force base in central Israel from where it can be deployed immediately in case of an emergency, the source told AFP.

The system, developed by Israel's Rafael Advanced Defence Systems with the help of US funding, is designed to intercept rockets and artillery shells fired from a range of between four and 70 kilometres (three and 45 miles).

Each battery comprises detection and tracking radar, state-of-the-art fire control software and three launchers, each with 20 interceptor missiles, the military source said.

Militants in Gaza and those allied with Lebanon's Hezbollah militia have fired thousands of projectiles at Israel in the past.

The system is likely to be deployed first along the border of the Hamas-run Gaza Strip, from where militants fired a daily barrage of home-made rockets prompting Israel to launch a devastating 22-day offensive in December 2008.

It will then be deployed along the Lebanese border, from where Hezbollah militants fired some 4,000 rockets into northern Israel during a 2006 war. It was that experience which prompted the development of Iron Dome.

Israel believes Hezbollah now has an arsenal of some 40,000 rockets.

In May, US President Barack Obama asked Congress to give Israel 205 million dollars to develop the system, on top of the annual three billion dollars Israel receives from Washington.

Iron Dome will join the Arrow long-range ballistic missile defence system in an ambitious multi-layered programme to protect Israeli cities from rockets and missiles fired from Lebanon, the Gaza Strip, Syria and Iran.

A third system, known as David's Sling, it currently being developed with the aim of countering medium-range missiles.