Israeli holding company Delek Group Ltd. (DLEKG.TV) said late Wednesday its board of directors has approved a plan to increase its holdings in Noble Energy Inc. (NBL) to up to 4%.

Delek currently owns 2.7% of U.S.-based Noble, which it acquired for a total investment of $307 million.

Delek said it plans to spend an additional $140 million in buying shares of Noble, and will make small purchases over the coming months.

Delek said it will continue negotiations with a group of banks to expand its non-recourse credit in order to finance the purchase of Noble shares.

Two Delek subsidiaries, along with Delek, own the rights to Israel's largest natural gas field, which contains about 6 trillion cubic feet of natural gas.

These companies recently signed a long-term deal worth at least $11 billion to supply natural gas to the Israel Electric Company, starting in 2012.

A more recent discovery, the Leviathan field, also off Israel's coast and controlled by Noble, may contain up to 16 trillion cubic feet of natural gas, but the field hasn't yet entered the production phase and its size is based on preliminary estimates.

Delek has global interests mainly in energy, real estate and the automotive sectors.

At 0800 GMT, shares of Delek were up 10.70 shekels ($2.84), or 1.2%, at ILS926.70, in a higher Tel Aviv market.

-By Sara Toth Stub, contributing to Dow Jones Newswires; saratoth@gmail.com