* Israeli fears of Iran, Syria prompt Swiss-style shelters
* Defence official plays down talk of imminent conflict
Then he ran into a solution of sorts.
"I heard complaints about the lack of bomb shelters, and suddenly I saw, just five minutes away, an underground parking lot," he told Reuters in an interview.
"I thought: Why aren't we exploiting these spaces?"
The rockets of the December-January war against Palestinian Hamas, like those that rained down during the 2006 conflict with Lebanon's Hezbollah guerrillas, were seen by many Israelis as a preface to a wider showdown involving Iran and its ally Syria.
The potential for military conflict with those countries has sent Vilnai, an ex-general responsible for civil defence, on weekly missions to assess the readiness of frontier communities and urban centres.
It's a touchy task given the tacit admission that Israel, which long championed lightning force to win wars well away from its slender home front, may now be hunkering down in the face of an Iranian nuclear programme that is too big to tackle alone.
Vilnai, giving his first extensive public account of the often secret planning, said there was no specific imminent threat to address. He preferred to speak in terms of deterrence.
"It's important to show your enemy that they can't surprise you," he said during a helicopter tour of Safed and Tiberias, towns near the Lebanese border which have the added headache of earthquake alerts, as they straddle the Syrian-African rift.
At 65, Vilnai radiates confidence in Israel's armed forces, of which he was once deputy chief. He sees no clash with the worst-case thinking that, he says, comes with his current job.
His role, he says, is to continue implementing provisions ordered after Iraqi missiles struck Israel in the 1991 Gulf war. Since 1992, the law has required all new homes to include a reinforced room that can be sealed off for blast-protection.
These "safe rooms" helped Israel withstand thousands of Hamas and Hezbollah battlefield rockets, but could not be relied on in the face of Iran's ballistic Shehab missiles and Syrian Scuds, especially if they carried non-conventional warheads.
WAR WATCH
So Vilnai wants highway tunnels and subway stations to double as capacious, Swiss-style nuclear shelters. Gas masks distributed to Israelis for the 2003 Iraq war are to be reissued next year, a precaution Vilnai attributes to the suspected chemical weapons projects of Syria and al Qaeda-style groups.
In Safed, he inspected a municipal bunker for crisis management, and nodded approvingly as the mayor, Ilan Shochat, recounted putting staff through regular emergency drills.
"There's no such thing as the 'last' exercise in Israel, only the 'previous' exercise," Vilnai said. "To my regret, it's like wars -- there's always another one to prepare for." Troubled by Tehran's hostile rhetoric, Israel has hinted it could hit Iranian nuclear sites pre-emptively. That stirred up speculation that Israel's civil defences anticipate retaliatory strikes threatened by Tehran.
Iran denies it is seeking to build nuclear bombs. Israel, which has not confirmed it has nuclear weapons, is believed to have the region's only atomic arsenal.
Vilnai brushes off the idea that he might be working to meet some secret deadline for an imminent sneak attack on Iran, which is weighing a deal with world powers on curbing its uranium enrichment, a process with bomb-making potential.
The Lebanon and Gaza conflicts revealed faults in the functions of some Israeli municipal shelters, so much of Vilnai's time is spent finding funds for their restoration.
In Safed, where many buildings are too old or small to include "safe rooms", Vilnai's team offered help in reinforcing stairwells or advising residents on which of their furnishings might be sturdy enough to hide under.
Asked about the more ambitious nuclear shelters he envisages for Tel Aviv and coastal Haifa, Vilnai did not sound rushed.
"There's no country in the world that is fully braced for this (nuclear war)," he said. "But we need to prepare. We are at the preliminary stage. In general, I'm thinking 10-20 years ahead."
Vilnai, whose centre-left Labour party sits in an often uneasy coalition led by rightist Prime Minister Benjamin Netanyahu, echoed the Israeli leader's assessment that Iran is the biggest challenge to the security of the Jewish state.
Yet Defence Minister and Labour leader Ehud Barak set a new tone last month by contesting Netanyahu's assertions that a nuclear-armed Iran could potentially destroy Israel. (Editing by Dominic Evans)
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