The Jerusalem Post reports that given the planned cuts in the 2012 defense budget, which many believe will be carried over for several years, the government may ask companies developing the gas fields to contribute to the cost of acquiring new warships.
The primary companies involved are Houston's Noble Energy Inc. and its key Israeli partner, the Delek Group headed by tycoon Yitzhak Tshuva.
They discovered the 125-square-mile Leviathan field, containing 16 trillion cubic feet of natural gas, and the smaller Tamar, which has reserves of 8.4 tcf, in 2009-10. Tamar is expected to produce first, in 2013.
Neighboring Lebanon, which is technically at war with Israel, claims that Leviathan, the largest field yet found, runs into its territorial waters. Israel rejects that claim. The Iranian-backed Hezbollah has threatened military action to prevent Lebanese energy reserved being "looted."
Israel has vowed to defend its gas fields. It fears that the Palestinian Hamas group, which rules the Gaza Strip where gas has also been found, could attack offshore drilling platforms and pipelines as well.
"Israel's concern is that Hezbollah and Hamas will try to attack the gas fields at sea in explosives-laden ships or with anti-ship missiles," the Post's defense correspondent Yaakov Katz reported.
Protecting Israel's newfound strategic energy assets will mean enlarging the 7,000-strong navy, which had been planned for some time anyway.
It is scheduled to get three new Dolphin class submarines from Howaldtswerke Deutsche Werft yards in Kiel, Germany, to add to the three it operates as a strategic force focused primarily on Iran.
As the navy is transformed from what was essentially a coastal force operating primarily in the Mediterranean into a blue-water ranging southward into the Red Sea and Arabian Sea, it will also need more long-range surface craft.
Navy chiefs have been pressing for at least two new major missile-armed corvettes to protect Israeli shipping lanes on top of the three Sa'ar-5 and eight Sa'ar-4.5 class corvettes currently in service.
But smaller vessels may be preferable for offshore gas field defense. The government may decide to go for Super Dvora-class ships built by state-owned Israel Aerospace Industries and Shaldag-class vessels produced by Israel Shipyards in Haifa.
In August, the navy was reported to be testing a missile defense system under development by the Defense Ministry's Research and Development Directorate.
This stems from concerns that Hezbollah, and to a lesser extent Hamas, have acquired Iranian-supplied anti-ship missiles that could be used against gas field platforms.
Hezbollah severely damaged the Israeli corvette Hanit early in their 34-day war in 2006 with a Chinese-designed C-802 anti-ship missile and sank an Egyptian freighter off the Lebanese coast.
Iran heightened Israeli concerns when it sent a naval corvette and a supply ship into the eastern Mediterranean in July via the Suez Canal, the first Iranian navy ships in the region since the Islamic Revolution in 1979.
The Iranian ships visited Tartous in Syria, Tehran's key Arab ally. There's been speculation Iran seeks to open a naval base there.
"While the navy is traditionally responsible for defending Israel's coast and its sea-based natural resources, it has told the government that it does not have enough ships and platforms to effectively defend future oil and gas rigs," Katz reported.
It's not clear what type and number of patrol vessels would be required to protect not just the gas fields but the pipelines through which Israel plans to pump the gas ashore as well as to the island of Cyprus 150 miles to the north.
Leviathan supposedly extends into Cypriot waters. The plan is to combine Israeli and Cypriot gas production and pump it via an underwater pipeline to Europe via Greece.
This has angered Turkey, which insists the Greek Cypriots in the southern part of the island, divided since 1974, can only drill with the consent of the Turkish Cypriot minority in the north.
Turkey, which is feuding with its former ally Israel, has threatened to send its navy in to prevent exploration off Cyprus.